Cool SQL Features

Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | @connor_mc_dwww.youtube.com/c/ConnorMcDonaldOracle 1
SQL> select sample_font
2 from dual ;
Can you read this ?
Note: Small fonts in this presentation

Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | @connor_mc_dwww.youtube.com/c/ConnorMcDonaldOracle
bio
8

make you more successful with Oracle

Copyright © 2015, Oracle and/or its affiliates. All rights reserved. |
SQL-lectric !!!
Connor McDonald
Developer Advocate for SQL
2016
Oracle Confidential –

why talk about SQL
(reason 1)
12

People are (re)learning...
13

...SQL is pretty important
14

“….the complexity of dealing with a
non-ACID data store in every part of
our business logic would be too
great, and there was simply no way
our business could function without
SQL queries.”
Google, VLDB 2013
“[Facebook] started in the Hadoop
world. We are now bringing in
relational to enhance that. ... [we]
realized that using the wrong
technology for certain kinds of
problems can be difficult.”
Ken Rudin, Facebook, TDWI 2013
15
http://tdwi.org/articles/2013/05/06/facebooks-relational-platform.aspxhttps://www.linkedin.com/groups/Find-out-why-Google-decided-4434815.S.273792742

why talk about SQL
(reason 2)
16

why talk about SQL
(reason 3)
19

we all want to be cool 
20

"microservices"
21

"simple function"
22
"insulated data access"
"test in isolation"
SQL> SELECT sal
2 FROM EMP
3 WHERE EMPNO = 12

its all about the SQL
23

this session

my favourites

strong focus on 12c

Favourite:
subquery factoring
27

WITH clause
28

SQL> WITH last_hire AS
2 ( select deptno, max(hiredate)
3 from emp
4 group by deptno
5 )
6 select * from last_hire;
DEPTNO MAX(HIRED
---------- ---------
30 03-DEC-81
20 12-JAN-83
10 23-JAN-82
29

"gee.......wow"
30

why is it cool ?
31

good solution metaphor
32

here's the problem
33

we're awful at set theory....
34

...set theory is awful 
35

not our fault
36

Codd & Date
37

"data is represented as mathematical n-ary relations, an n-ary
relation being a subset of the Cartesian product of n domains."
38

humans are procedural
40

business analysts...
procedural analysis
41

technical analysts...
procedural specifications
42

programmers
procedural programs
43

procedural
44
relational

good solution metaphor
45

"First, get the total salary paid by department...
SQL> WITH dept_salaries AS (
2 SELECT dname, SUM(sal) dept_sal
3 FROM emp e, dept d
4 WHERE e.deptno = d.deptno
5 GROUP BY dname),
46

"...then get the average of these totals...
6 avg_sal AS ( SELECT AVG(dept_sal) avsal
7 FROM dept_salaries)
47

"...then list those departments above average."
8 SELECT * FROM dept_salaries d, avg_sal a
9 WHERE d.dept_sal > a.avsal
10 ORDER BY d.dname;
48

5 GROUP BY dname),
6 avg_sal AS ( SELECT AVG(dept_sal) avsal
9 WHERE d.dept_sal > a.avsal
49

procedural approach....
50

...set based solution
51

things to note...
52

execution plan
53

two possibilities
54

temporary storage
55

----------------------------------------------------------------------
| Id | Operation | Name |
----------------------------------------------------------------------
| 0 | SELECT STATEMENT | |
| 1 | TEMP TABLE TRANSFORMATION | |
| 2 | LOAD AS SELECT | |
| 3 | HASH GROUP BY | |
| 4 | MERGE JOIN | |
| 5 | TABLE ACCESS BY INDEX ROWID| DEPT |
| 6 | INDEX FULL SCAN | PK_DEPT |
| 7 | SORT JOIN | |
| 8 | TABLE ACCESS FULL | EMP |
| 9 | SORT ORDER BY | |
| 10 | NESTED LOOPS | |
| 11 | VIEW | |
| 12 | SORT AGGREGATE | |
| 13 | VIEW | |
| 14 | TABLE ACCESS FULL | SYS_TEMP_0FD9D6624_AF422F5 |
| 15 | VIEW | |
| 16 | TABLE ACCESS FULL | SYS_TEMP_0FD9D6624_AF422F5 |
----------------------------------------------------------------------
56

SQL> alter session set sql_trace = true;
Session altered.
5 GROUP BY dname),
6 avg_sal AS ( SELECT AVG(dept_sal) asal
9 WHERE d.dept_sal > a.asal
DNAME DEPT_SAL ASAL
-------------- ---------- ----------
RESEARCH 21750 19350
SQL> alter session set sql_trace = false;
Session altered.
57

PARSING IN CURSOR #12 len=179 dep=1 uid=0 oct=1...
CREATE GLOBAL TEMPORARY
TABLE "SYS"."SYS_TEMP_0FD9D6625_AF422F5"
("C0" VARCHAR2(14),"C1" NUMBER )
IN_MEMORY_METADATA CURSOR_SPECIFIC_SEGMENT
STORAGE (OBJNO 4254950949 ) NOPARALLEL
END OF STMT
58

no temporary storage
59

------------------------------------------------------
| Id | Operation | Name |
------------------------------------------------------
| 0 | SELECT STATEMENT | |
| 1 | SORT ORDER BY | |
| 2 | NESTED LOOPS | |
| 3 | VIEW | |
| 4 | SORT AGGREGATE | |
| 5 | VIEW | |
| 6 | HASH GROUP BY | |
| 8 | TABLE ACCESS BY INDEX ROWID| DEPT |
| 10 | SORT JOIN | |
| 12 | VIEW | |
| 13 | SORT GROUP BY | |
| 15 | TABLE ACCESS BY INDEX ROWID | DEPT |
| 17 | SORT JOIN | |
------------------------------------------------------
60

explicit control
61

2 SELECT /*+ INLINE */ dname, SUM(sal) dept_sal
5 GROUP BY dname),
62

2 SELECT /*+ MATERIALIZE*/ dname, SUM(sal) dept_sal
5 GROUP BY dname),
63

undocumented .... sort of
64

useful control over optimizer
65

useful control over database links
66

... more on WITH later
67

Favourite:
temporal validity

very common
70

when is a row "valid"
71

SQL> CREATE TABLE emp_temporal (
2 empno NUMBER,
3 name VARCHAR2(30),
4 sal NUMBER,
5 deptno NUMBER,
6 start_dt DATE,
7 end_dt DATE,
8
9 );
Table created.
72

12c - part of the definition
73

SQL> CREATE TABLE emp_temporal (
2 empno NUMBER,
3 name VARCHAR2(30),
4 sal NUMBER,
5 deptno NUMBER,
6 start_dt DATE,
7 end_dt DATE,
8 PERIOD FOR valid_range (start_dt, end_dt)
9 );
Table created.
74

examples
75

SQL> select * from emp_temporal
2 order by empno, start_dt;
EMPNO NAME SAL DEPTNO START_DT END_DT
---------- ------------ ---------- ---------- --------- ---------
7369 SMITH 806 20 01-JAN-14 01-MAR-14
7369 SMITHX 8060 21 02-MAR-14 01-OCT-14
7499 ALLEN 1606 30 01-JAN-14 01-MAR-14
7499 ALLENX 16060 31 02-MAR-14 01-OCT-14
7521 WARD 1256 30 01-JAN-14 01-MAR-14
7521 WARDX 12560 31 02-MAR-14 01-OCT-14
7566 JONES 2981 20 01-JAN-14 01-MAR-14
7566 JONESX 29810 21 02-MAR-14 01-OCT-14
7654 MARTIN 1256 30 01-JAN-14 01-MAR-14
7654 MARTINX 12560 31 02-MAR-14 01-OCT-14
7698 BLAKE 2856 30 01-JAN-14 01-MAR-14
76

SQL> select * from emp_temporal
2 as of period for valid_range '01-FEB-14';
EMPNO NAME SAL DEPTNO START_DT END_DT
---------- ------------ ---------- ---------- --------- ---------
7369 SMITH 806 20 01-JAN-14 01-MAR-14
7499 ALLEN 1606 30 01-JAN-14 01-MAR-14
7521 WARD 1256 30 01-JAN-14 01-MAR-14
7566 JONES 2981 20 01-JAN-14 01-MAR-14
7654 MARTIN 1256 30 01-JAN-14 01-MAR-14
77

so what's happening ?
78

a slight digression
79

Favourite:
query expansion
80

SQL> set autotrace traceonly stat
SQL> select * from MY_STUFF
2 where CREATED > sysdate
Statistics
------------------------------------------
651 recursive calls
0 db block gets
2243 consistent gets
24 physical reads

SQL> variable c clob
SQL> begin
2 dbms_utility.expand_sql_text
3 ( 'select * from MY_STUFF'||
4 'where created > sysdate',:c);
5 end;
6 /
PL/SQL procedure successfully completed.
SQL> print c

SQL> create or replace
2 view MY_STUFF as
3 select
4 o.owner,
5 o.created,
6 s.bytes,
7 s.tablespace_name
8 from
9 dba_segments s,
10 all_objects o
11 where o.owner = s.owner
12 and o.object_name = s.segment_name;
View created.

SELECT "A1"."OWNER" "OWNER",
"A1"."NAME" "NAME",
"A1"."CREATED" "CREATED",
"A1"."BYTES" "BYTES",
"A1"."TABLESPACE_NAME" "TABLESPACE_NAME"
FROM (SELECT "A2"."OWNER" "OWNER",
"A2"."OBJECT_NAME" "NAME",
"A2"."CREATED" "CREATED",
"A3"."BYTES" "BYTES",
"A3"."TABLESPACE_NAME" "TABLESPACE_NAME" FROM (SELECT "A4"
."OWNER" "OWNER",
"A4"."SEGMENT_NAME" "SEGMENT_NAME",
"A4"."PARTITION_NAME" "PARTITION_NAME",
"A4"."SEGMENT_TYPE" "SEGMENT_TYPE",
"A4"."SEGMENT_SUBTYPE" "SEGMENT_SUBTYPE",
"A4"."TABLESPACE_NAME" "TABLESPACE_NAME",
"A4"."HEADER_FILE" "HEADER_FILE",
"A4"."HEADER_BLOCK" "HEADER_BLOCK",
DECODE(BITAND("A4"."SEGMENT_FLAGS",131072),131072,
"A4"."BLOCKS",DECODE(BITAND("A4"."SEGMENT_FLAGS",1),1,
"SYS"."DBMS_SPACE_ADMIN"."SEGMENT_NUMBER_BLOCKS"("A4"."TABLESPACE_ID",
"A4"."RELATIVE_FNO",
"A4"."HEADER_BLOCK",
"A4"."SEGMENT_TYPE_ID",
"A4"."BUFFER_POOL_ID",
"A4"."SEGMENT_FLAGS",
"A4"."SEGMENT_OBJD",
"A4"."BLOCKS"),
"A4"."BLOCKS"))*"A4"."BLOCKSIZE" "BYTES",
DECODE(BITAND("A4"."SEGMENT_FLAGS",131072),131072,

"A4"."BLOCKS"),
"A4"."BLOCKS")) "BLOCKS",DECODE(BITAND("A4"."SEGMENT_FLAGS",131072),131072,
"A4"."EXTENTS",DECODE(BITAND("A4"."SEGMENT_FLAGS",1),1,
"SYS"."DBMS_SPACE_ADMIN"."SEGMENT_NUMBER_EXTENTS"("A4"."TABLESPACE_ID",
"A4"."RELATIVE_FNO",
"A4"."EXTENTS"),
"A4"."EXTENTS")) "EXTENTS",
"A4"."INITIAL_EXTENT" "INITIAL_EXTENT",
"A4"."NEXT_EXTENT" "NEXT_EXTENT",
"A4"."MIN_EXTENTS" "MIN_EXTENTS",
"A4"."MAX_EXTENTS" "MAX_EXTENTS",
"A4"."MAX_SIZE" "MAX_SIZE",
"A4"."RETENTION" "RETENTION",
"A4"."MINRETENTION" "MINRETENTION",
"A4"."PCT_INCREASE" "PCT_INCREASE",
"A4"."FREELISTS" "FREELISTS",
"A4"."FREELIST_GROUPS" "FREELIST_GROUPS",
"A4"."RELATIVE_FNO" "RELATIVE_FNO",

"A198"."SUBNAME" "PARTITION_NAME",
"A196"."OBJECT_TYPE" "SEGMENT_TYPE",
"A195"."TYPE#" "SEGMENT_TYPE_ID",DECODE(BIT
AND("A195"."SPARE1",2097408),2097152,'SECUREFILE',256,'ASSM','MSSM')
"SEGMENT_SUBTYPE",
"A197"."TS#" "TABLESPACE_ID",
"A197"."NAME" "TABLESPACE_NAME",
"A197"."BLOCKSIZE" "BLOCKSIZE",
"A194"."FILE#" "HEADER_FILE",
"A195"."BLOCK#" "HEADER_BLOCK",
"A195"."BLOCKS"*"A197"."BLOCKSIZE" "BYTES",
"A195"."BLOCKS" "BLOCKS",
"A195"."EXTENTS" "EXTENTS",
"A195"."INIEXTS"*"A197"."BLOCKSIZE" "INITIAL_EXTENT",
"A195"."EXTSIZE"*"A197"."BLOCKSIZE" "NEXT_EXTENT",
"A195"."MINEXTS" "MIN_EXTENTS",
"A195"."MAXEXTS"
"MAX_EXTENTS",DECODE(BITAND("A195"."SPARE1",4194304),4194304,
"A195"."BITMAPRANGES",NULL) "MAX_SIZE",TO_CHAR(DECODE(
BITAND("A195"."SPARE1",2097152),2097152,
DECODE("A195"."LISTS",0,'NONE',1,'AUTO',2,'MIN',3,'MAX',4,'DEFAULT','INVALID'
),NULL))
"RETENTION",DECODE(BITAND("A195"."SPARE1",2097152),2097152,
"A195"."GROUPS",NULL)
"MINRETENTION",DECODE(BITAND("A197"."FLAGS",3),1,TO_NUMBER(NULL),
"A195"."EXTPCT") "PCT_INCREASE",DECODE(BITAND("A197"."FLAGS",32),32,
TO_NUMBER(NULL),DECODE("A195"."LISTS",0,1,
"A195"."LISTS"))
"FREELISTS",DECODE(BITAND("A197"."FLAGS",32),32,TO_NUMBER(NULL),DECODE("A195"
."GROUPS",0,1,

DECODE(BITAND("A209"."PROPERTY",8192),8192,'NESTED TABLE','TABLE')
"OBJECT_TYPE",
2 "OBJECT_TYPE_ID",5 "SEGMENT_TYPE_ID",
"A209"."OBJ#" "OBJECT_ID",
"A209"."TS#" "TS_NUMBER" FROM "SYS"."TAB$" "A209" WHERE
BITAND("A209"."PROPERTY",1024)=0) UNI
ON ALL (SELECT 'TABLE PARTITION' "OBJECT_TYPE",19 "OBJECT_TYPE_ID",5
"SEGMENT_TYPE_ID",
"A208"."TS#" "TS_NUMBER" FROM "SYS"."TABPART$" "A208") UNION ALL
(SELECT 'CLUSTER' "OBJECT_TYPE",3 "OBJECT_TYPE_ID",5 "SEGMENT_TYPE_ID",
"A207"."TS#" "TS_NUMBER" FROM "SYS"."CLU$" "A207") UNION ALL
(SELECT DECODE("A206"."TYPE#",8,'LOBINDEX','INDEX') "OBJECT_TYPE",1
"OBJECT_TYPE_ID",6 "SEGMENT_TYPE_ID",
"A206"."TS#" "TS_NUMBER" FROM "SYS"."IND$" "A206" WHERE "A206"."TYPE#"=1 OR
"A206"."TYPE#"=2 OR
"A206"."TYPE#"=3 OR
"A206"."TYPE#"=4 OR
"A206"."TYPE#"=6 OR

"A205"."TS#" "TS_NUMBER" FROM "SYS"."INDPART$" "A205") UNION ALL
(SELECT 'LOBSEGMENT' "OBJECT_TYPE",21 "OBJECT_TYPE_ID",8 "SEGMENT_TYPE_ID",
"A204"."LOBJ#" "OBJECT_ID",
"A204"."TS#" "TS_NUMBER" FROM "SYS"."LOB$" "A204" WHERE
BITAND("A204"."PROPERTY",64)=0 OR
BITAND("A204"."PROPERTY",128)=128) UNION ALL
(SELECT 'TABLE SUBPARTITION' "OBJECT_TYPE",34 "OBJECT_TYPE_ID",5
"SEGMENT_TYPE_ID",
"A203"."TS#" "TS_NUMBER" FROM "SYS"."TABSUBPART$" "A203") UNION ALL
(SELECT 'INDEX SUBPARTITION' "OBJECT_TYPE",35 "OBJECT_TYPE_ID",6
"SEGMENT_TYPE_ID",
"A202"."TS#" "TS_NUMBER" FROM "SYS"."INDSUBPART$" "A202") UNION ALL
(SELECT DECODE("A201"."FRAGTYPE$",'P','LOB PARTITION','LOB SUBPARTITION')
"OBJECT_TYPE",DECODE("A201"."FRAGTYPE$",'P',40,41) "OBJECT_TYPE_ID",8
"SEGMENT_TYPE_ID",
"A201"."FRAGOBJ#" "OBJECT_ID",
"A201"."TS#" "TS_NUMBER" FROM "SYS"."LOBFRAG$" "A201")) "A196",
"SYS"."SEG$" "A195",

"A195"."FILE#"="A194"."RELFILE#") UNION ALL
(SELECT NVL("A193"."NAME",'SYS') "OWNER",
"A191"."NAME" "SEGMENT_NAME",NULL "PARTITION_NAME",
DECODE("A190"."TYPE#",1,'ROLLBACK',10,'TYPE2 UNDO') "SEGMENT_TYPE",
"A190"."TYPE#" "SEGMENT_TYPE_ID",NULL "SEGMENT_SUBTYPE",
"A190"."MAXEXTS"
"A190"."BITMAPRANGES",NULL) "MAX_SIZE",NULL "RETENTION",NULL "MINRETENTION",
"A190"."EXTPCT"
"PCT_INCREASE",DECODE(BITAND("A192"."FLAGS",32),32,TO_NUMBER(NULL),DECODE("A1
90"."LISTS",0,1,
"A190"."LISTS"))
"FREELISTS",DECODE(BITAND("A192"."FLAGS",32),32,TO_NUMBER(NULL),
DECODE("A190"."GROUPS",0,1,"A190"."GROUPS")) "FREELIST_GROUPS",
"A190"."FILE#" "RELATIVE_FNO",BITAND("A190"."CACHEHINT",3)
"BUFFER_POOL_ID",BITAND("A190"."CACHEHINT",12)/4 "FLASH_CACHE",
BITAND("A190"."CACHEHINT",48)/16 "CELL_FLASH_CACHE",NVL("A190"."SPARE1",0)
"SEGMENT_FLAGS",

"A191"."TS#"="A189"."TS#" AND
(SELECT NVL("A188"."NAME",'SYS') "OWNER",
TO_CHAR("A185"."FILE#")||'.'||TO_CHAR("A186"."BLOCK#") "SEGMENT_NAME",NULL
"PARTITION_NAME",
DECODE("A186"."TYPE#",2,'DEFERRED ROLLBACK',3,
'TEMPORARY',4,'CACHE',9,'SPACE HEADER','UNDEFINED') "SEGMENT_TYPE",
"A186"."MAXEXTS"
"A186"."BITMAPRANGES",NULL) "MAX_SIZE",NULL
"RETENTION",NULL
"A186"."EXTPCT")
"PCT_INCREASE",DECODE(BITAND("A187"."FLAGS",32),32,TO_NUMBER(NULL),DECODE("A1
86"."LISTS",0,1,
"A186"."LISTS"))
"FREELISTS",DECODE(BITAND("A187"."FLAGS",32),32,TO_NUMBER(NULL),DECODE("A186"
."GROUPS",0,1,

"A186"."TYPE#"<>6 AND
"A186"."TYPE#"<>8 AND
"A186"."TYPE#"<>10 AND
"A186"."TYPE#"<>11 AND
"A186"."TS#"="A185"."TS#"
AND
(SELECT NVL("A184"."NAME",'SYS') "OWNER",'HEATMAP' "SEGMENT_NAME",
NULL "PARTITION_NAME",'SYSTEM STATISTICS' "SEGMENT_TYPE",
"A183"."BLO
CKSIZE" "BLOCKSIZE",
"A182"."MAXEXTS"
"A182"."BITMAPRANGES",NULL) "MAX_SIZE",NULL "RETENTION",NULL
"A182"."EXTPCT")
"PCT_INCREASE",DECODE(BITAND("A183"."FLAGS",32),32,TO_NUMBER(NULL),DEC

"SYS"."TS$" "A183",
"SYS"."SEG$" "A182",
"SYS"."FILE$" "A181" WHERE "A182"."TS#"="A183"."TS#" AND
"A182"."USER#"="A184"."USER#"(+) AND
"A182"."TYPE#"=11 AND
"A182"."TS#"="A181"."TS#" AND
"A182"."FILE#"="A181"."RELFILE#")) "A4") "A3", (SELECT "A5"."NAME" "OWNER",
"A6"."NAME" "OBJECT_NAME",
"A6"."SUBNAME" "SUBOBJECT_NAME",
"A6"."DATAOBJ#" "DATA_OBJECT_ID",DECODE("A6"."TYPE#",0,'NEXT OBJECT',1,'INDEX',
2,'TABLE',3,'CLUSTER',4,'VIEW',5,'SYNONYM
',6,'SEQUENCE',7,'PROCEDURE',8,'FUNCTION',9,'PACKAGE',11,'PACKAGE BODY',12,
'TRIGGER',13,'TYPE',14,'TYPE BODY',19,'TABLE PARTITION',20,'INDEX PARTITION',
21,'LOB',22,'LIBRARY',23,'DIRECTORY',24,'QUEUE',28,'JAVA SOURCE',29,'JAVA CLASS',30,
'JAVA RESOURCE',32,'INDEXTYPE',33,'OPERATOR',34,
'TABLE SUBPARTITION',35,'INDEX SUBPARTITION',40,'LOB PARTITION',41,'LOB SUBPARTITION',42
,NVL( (SELECT 'REWRITE EQUIVALENCE' "'REWRITEEQUIVALENCE'" FROM SYS."SUM$" "A52" WHERE
"A52"."OBJ#"="A6"."OBJ#" AND
BITAND("A52"."XPFLAGS",8388608)=8388608),'MATERIALIZED VIEW'),43,'DIMENSION',
44,'CONTEXT',46,'RULE SET',47,'RESOURCE PLAN',48,'CONSUMER GROUP',55,'XML SCHEMA',56,'JAVA
DATA',57,'EDITION',59,'RULE',
60,'CAPTURE',61,'APPLY',62,'EVALUATION CONTEXT',66,'JOB',67,'PROGRAM',68,'JOB CLASS',69,
'WINDOW',72,'SCHEDULER GROUP',74,'SCHEDULE',79,'CHAIN',81,'FILE GROUP',82,'MINING
MODEL',87,'ASSEMBLY',90,'CREDENTIAL',92,'CUBE
DIMENSION',93,'CUBE',94,'MEASURE FOLDER',95,'CUBE BUILD PROCESS',100,'FILE WATCHER',
101,'DESTINATION',114,'SQL TRANSLATION PROFILE',115,'UNIFIED AUDIT POLICY','UNDEFINED')
"OBJECT_TYPE",
"A6"."CTIME" "CREATED",

16 ...
93
more
pages

back to temporal validity
94

SQL> variable c clob
SQL> begin
2 dbms_utility.expand_sql_text(
3 q'{select * from emp_temporal
4 as of period for valid_range '01-FEB-14'}',:c);
6 end;
7 /

SQL> print c
C
------------------------------------------------
SELECT
"A1"."EMPNO"
...
FROM (
SELECT "A2"."EMPNO" "EMPNO",
"A2"."NAME"
FROM "SCOTT"."EMP_TEMPORAL" "A2"
WHERE ("A2"."START_DT" IS NULL
OR "A2"."START_DT"<='01-FEB-14')
AND ("A2"."END_DT" IS NULL
OR "A2"."END_DT">'01-FEB-14')
) "A1"
96

existing tables
97

SQL> desc EMPLOYEE
Name Null? Type
------------------------- -------- ---------------
EMPNO NUMBER(4)
ENAME VARCHAR2(10)
JOB VARCHAR2(9)
MGR NUMBER(4)
HIREDATE DATE
SAL NUMBER(7,2)
COMM NUMBER(12,2)
DEPTNO NUMBER(2)
SQL> alter table EMPLOYEE add period for TIME_RANGE;
Table altered.
98

SQL> desc EMPLOYEE
Name Null? Type
------------------------- -------- ---------------
EMPNO NUMBER(4)
ENAME VARCHAR2(10)
JOB VARCHAR2(9)
MGR NUMBER(4)
HIREDATE DATE
SAL NUMBER(7,2)
COMM NUMBER(12,2)
DEPTNO NUMBER(2)
still looks the same ?
99

SQL> select column_name , hidden_column
2 from USER_TAB_COLS
3 where table_name = 'EMPLOYEE'
4 order by column_id;
COLUMN_NAME HIDDEN_COLUMN
------------------------------ -------------
EMPNO NO
ENAME NO
JOB NO
MGR NO
HIREDATE NO
SAL NO
COMM NO
DEPTNO NO
TIME_RANGE_START YES
TIME_RANGE_END YES
TIME_RANGE YES
100

multi temporal validity
101

SQL> alter table EMP_TEMPORAL add period for CAL_RANGE;
Table altered.
SQL> alter table EMP_TEMPORAL add period for FINYR_RANGE;
Table altered.
102

"room to grow"
103

no temporal constraints
104

SQL> alter table EMP_TEMPORAL add primary key (empno);
Table altered.
SQL> insert into EMP_TEMPORAL
2 (empno, name, start_dt, end_dt )
3 values (20,'BROWN', '01-FEB-14','01-MAR-14');
1 row created.
3 values (20,'BROWN', '01-MAY-14','01-SEP-14');
insert into EMP_TEMPORAL
*
ERROR at line 1:
ORA-00001: unique constraint (SYS_C009892) violated
105

add START_DT to primary key ?

no temporal validation
107

3 values (10,'JONES', '01-JAN-14','01-MAY-14');
1 row created.
3 values (10,'JONES', '01-FEB-14','01-MAR-14');
1 row created.

no (native) temporal DML
109

SQL> update EMP_TEMPORAL
2 as of period for valid_range '01-FEB-14'
3 set sal = 10
4 where empno = 20;
as of period for valid_range '01-FEB-14'
*
ERROR at line 2:
ORA-08187: snapshot expression not allowed here
110

SQL> update
2 ( select * from EMP_TEMPORAL
3 as of period for valid_range '01-FEB-14'
4 )
5 set sal = 10
6 where empno = 20;
1 row updated.
111

take note ..

"Temporal validity is not supported
with a multitenant container
database"
113
12.1.0.1

Favourite:
top-n simplifications
114

"5 most recently hired employees"
115

SQL> select empno, ename, hiredate
2 from emp
3 where rownum <= 5
4 order by hiredate desc;
EMPNO ENAME HIREDATE
---------- ---------- -------------------
7654 MARTIN 28/09/1981 00:00:00
7566 JONES 02/04/1981 00:00:00
7521 WARD 22/02/1981 00:00:00
7499 ALLEN 20/02/1981 00:00:00
7369 SMITH 17/12/1980 00:00:00
116

inline view
117

SQL> select *
2 from (
3 select empno, ename, hiredate
4 from emp
5 order by hiredate desc
6 )
7 where rownum <= 5;
---------- ---------- ---------
7876 ADAMS 23-MAY-87
7788 SCOTT 19-APR-87
...
118

------------------------------------------------
| Id | Operation | Name | Rows |
------------------------------------------------
| 0 | SELECT STATEMENT | | 5 |
|* 1 | COUNT STOPKEY | | |
| 2 | VIEW | | 14 |
|* 3 | SORT ORDER BY STOPKEY| | 14 |
| 4 | TABLE ACCESS FULL | EMP | 14 |
------------------------------------------------
119

SQL> select *
2 from (
3 select
4 empno, ename, hiredate,
5 row_number() over ( order by hiredate desc) rn
6 from emp
7 )
8 where rn <= 5;
120

-------------------------------------------------
-------------------------------------------------
|* 1 | VIEW | | 14 |
|* 2 | WINDOW SORT PUSHED RANK| | 14 |
-------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("RN"<=5)
2 - filter(ROW_NUMBER() OVER
( ORDER BY HIREDATE") DESC )<=5)
121

12c .... easier
122

2 from emp
4 fetch first 5 rows only;
---------- ---------- ---------
...
123

behind the scenes
124

-------------------------------------------------
-------------------------------------------------
|* 1 | VIEW | | 14 |
|* 2 | WINDOW SORT PUSHED RANK| | 14 |
-------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("from$_subquery$_002".
"rowlimit_$$_rownumber"<=5)
2 - filter(ROW_NUMBER() OVER
( ORDER BY HIREDATE") DESC )<=5)
125

variations
126

2 from emp
4 fetch first 1 row only;
---------- ---------- ---------
127

2 from emp
4 fetch first 5 row only;
---------- ---------- ---------
7934 MILLER 23-JAN-82
7900 JAMES 03-DEC-81
7902 FORD 03-DEC-81
128

2 from emp
4 fetch first 10 percent rows only;
---------- ---------- ---------
129

pagination
130

2 from emp
4 offset 5 rows fetch next 3 rows only;
---------- ---------- ---------
7839 KING 17-NOV-81
7654 MARTIN 28-SEP-81
7844 TURNER 08-SEP-81
131

can mimic rownum
132

2 from emp
---------- ---------- ---------
7369 SMITH 17-DEC-80
7499 ALLEN 20-FEB-81
7521 WARD 22-FEB-81
133

-----------------------------------------------
-----------------------------------------------
|* 1 | VIEW | | 14 |
|* 2 | WINDOW NOSORT STOPKEY| | 14 |
-----------------------------------------------
1 - filter("from$_subquery$_002"."rowlimit_$
2 - filter(ROW_NUMBER() OVER ( ORDER BY NULL ) <= 3
134

things to note
135

2 from emp
4 fetch LAST 5 rows only;
fetch LAST 5 rows only
*
ERROR at line 4:
ORA-00905: missing keyword
136

SQL> select *
2 from (
4 from emp
5 order by hiredate asc
6 fetch first 5 rows only
7 )
8 order by hiredate desc;
---------- ---------- ---------
7698 BLAKE 01-MAY-81
7566 JONES 02-APR-81
7521 WARD 22-FEB-81
137

or ...
138

2 from emp
4 offset ( select count(*)-5 from emp) rows
---------- ---------- ---------
7698 BLAKE 01-MAY-81
7566 JONES 02-APR-81
7521 WARD 22-FEB-81
139

----------------------------------------------
----------------------------------------------
|* 1 | VIEW | | 14 |
| 2 | WINDOW SORT | | 14 |
| 3 | TABLE ACCESS FULL| EMP | 14 |
| 4 | SORT AGGREGATE | | 1 |
| 5 | INDEX FULL SCAN | PK_EMP | 14 |
----------------------------------------------
140
ugh

no percent pagination
141

2 from emp
4 offset 20 percent fetch
5 next 10 percent rows only;
offset 20 percent fetch next 10 percent rows only
*
ERROR at line 4:
ORA-00905: missing keyword
142

2 from emp
4 offset
5 ( select 20/100*count(*) from emp) rows
6 fetch next 10 percent rows only;
---------- ---------- ---------
7902 FORD 03-DEC-81
143

PL/SQL quirk
144

"Note that in real life,
you would use bind variables
instead of hard-coded literals"
145
- Tom Kyte,
Oracle Magazine

SQL> variable x number
SQL> exec :x := 5
2 from emp
4 fetch first :x rows only;
---------- ---------- ---------
7900 JAMES 03-DEC-81
7902 FORD 03-DEC-81
146

SQL> declare
2 l_num number := 5;
3 begin
4 for i in (
6 from emp
8 fetch first l_num rows only
9 )
10 loop
11 null;
12 end loop;
13 end;
14 /
ERROR at line 1:
ORA-03113: end-of-file on communication channel
Process ID: 26618
Session ID: 25 Serial number: 53023
147

SQL> declare
2 l_num number := 5;
3 begin
4 for i in (
6 from emp
8 fetch first cast(l_num as number) rows only
9 )
10 loop
11 null;
12 end loop;
13 end;
14 /
148

Favourite:
pattern matching
149

analytics ... since 8.1.6
150
median
top n
moving average
etc

"analysis"
often
"patterns"
151

real example
152

AML
154
anti-money laundering

"Find 10 consecutive deposits in a
24 hour period, then
a withdrawal within three days of
the last deposit, at a different outlet"
155

ACCT TSTAMP WTHD_TSTAMP T AMT
---------- ------------------ ------------------ - ----------
54261 25/01/13 17:20:55 D 100
54261 25/01/13 17:56:58 D 165
54261 26/01/13 11:24:14 D 30
54261 26/01/13 11:47:53 D 45
54261 26/01/13 12:59:38 D 100
54261 26/01/13 13:26:04 D 80
54261 26/01/13 14:41:09 D 50
54261 26/01/13 14:53:12 D 50
54261 26/01/13 15:15:05 D 50
54261 26/01/13 15:51:17 D 50
54261 26/01/13 16:15:02 D 120
54261 26/01/13 16:36:51 D 100
54261 26/01/13 16:55:09 D 100
54261 26/01/13 18:07:17 26/01/13 18:07:17 W -500
156

hard...
157

pattern matching
158

SQL> select acct, tstamp, wthd_tstamp, txn_type, amt
2 from account_txns
3 MATCH_RECOGNIZE
4 (
5 partition by acct
6 order by tstamp
7 measures
8 dep.tstamp dep_tstamp,
9 wthd.tstamp wthd_tstamp
10
11 all rows per match
12 pattern ( dep{10,} wthd )
13 define
14 dep as
15 txn_type = 'D',
16 wthd as
17 txn_type = 'W'
18 and last(dep.tstamp)-first(dep.tstamp) < interval '1' day
19 and wthd.tstamp - last(dep.tstamp) < interval '3' day
20 and wthd.location != last(dep.location)
21 )
159

Favourite:
join enhancements

11.2
161

SQL> create table emp2 as
2 select * from emp;
Table created.
SQL> select *
2 from emp e,
3 emp2 e2,
4 dept d
5 where e.deptno = d.deptno(+)
6 and e2.deptno = d.deptno(+)
7 and e.empno = e2.empno
8 /
where e.deptno = d.deptno(+)
*
ERROR at line 5:
ORA-01417: a table may be outer joined to at most one other table
162

but ANSI syntax works …
163

12c
164

SQL> select *
2 from emp e,
3 emp2 e2,
4 dept d
5 where e.deptno = d.deptno(+)
6 and e2.deptno = d.deptno(+)
7 and e.empno = e2.empno
8 /
EMPNO ENAME JOB MGR
---------- ---------- --------- ----------
7934 MILLER CLERK 7782
...
165

correlated inline views
166

SQL> create table DEPT_BENEFITS as
2 select d.*, 10 benefits from dept d;
Table created.
SQL> insert into DEPT_BENEFITS
2 select d.*, 20 benefits from dept d;
4 rows created.
167

SQL> select e.empno, e.deptno, d.benefits
2 from emp e,
3 DEPT_BENEFITS d
4 where e.deptno = d.deptno
5 order by 1,3;
EMPNO DEPTNO BENEFITS
---------- ---------- ----------
7369 20 10
7369 20 20
7499 30 10
7499 30 20
7521 30 10
7521 30 20
...
...
168

"benefits for each employee"
169

SQL> select e.empno, d.deptno, b.benefits
2 from emp e,
3 ( select benefits
4 from DEPT_BENEFITS d
5 where d.deptno = e.deptno
6 ) b
7 order by 1,3;
where d.deptno = e.deptno
*
ERROR at line 5:
ORA-00904: "E"."DEPTNO": invalid identifier
170

CROSS APPLY
171

SQL> select e.empno, e.deptno, b.benefits
2 from emp e
3 CROSS APPLY
4 ( select benefits
7 ) b
8 order by 1,3;
---------- ---------- ----------
7369 20 10
7369 20 20
7499 30 10
...
...

"big deal"
173

SQL> select e.empno, d.deptno, b.benefits
2 from emp e,
3 ( select benefits
5
6 ) b
7
8 order by 1,3;
where d.deptno = e.deptno
174

"best benefit for each employee"
175

SQL> select e.empno, e.deptno, b.benefits
2 from emp e
3 CROSS APPLY
4 ( select benefits
7 order by benefits desc
8 fetch first 1 rows only
9 ) b
10 order by 1,3;
---------- ---------- ----------
7369 20 20
7499 30 20
7521 30 20
7566 20 20
7654 30 20
...
176

Favourite:
DML error logging
177

SQL> insert /*+ APPEND */ into MY_TABLE
2 select *
3 from MY_WHOPPING_GREAT_FAT_TABLE;
178
MY_WHOPPING_GREAT_FAT_TABLE;

2 select *
Elapsed: 06:12:34.00
184

2 select *
Elapsed: 06:12:34.00
ERROR at line 1:
ORA-00001: unique constraint (DEMO.WHOPPER_PK) violated
185

SQL> select count(*) from MY_TABLE;
COUNT(*)
----------
0
186

what we want
187

keep successful rows
188

skip / bypass bad rows
189

2 select *
3 from MY_WHOPPING_GREAT_FAT_TABLE
4 where "not a duplicate"
5 and "datatypes are ok"
6 and "foreign keys are ok"
7 and "check constraints are ok"
190

SQL> exec DBMS_ERRLOG.CREATE_ERROR_LOG('EMP')
191

ERR$_EMP
192

DBMS_ERRLOG.CREATE_ERROR_LOG (
dml_table_name IN VARCHAR2,
err_log_table_name IN VARCHAR2 := NULL,
err_log_table_owner IN VARCHAR2 := NULL,
...
193

SQL> desc ERR$_EMP
Name Null? Type
----------------------------- -------- ----------------
ORA_ERR_NUMBER$ NUMBER
ORA_ERR_MESG$ VARCHAR2(2000)
ORA_ERR_ROWID$ ROWID
ORA_ERR_OPTYP$ VARCHAR2(2)
ORA_ERR_TAG$ VARCHAR2(2000)
EMPNO VARCHAR2(4000)
ENAME VARCHAR2(4000)
JOB VARCHAR2(4000)
MGR VARCHAR2(4000)
HIREDATE VARCHAR2(4000)
SAL VARCHAR2(4000)
COMM VARCHAR2(4000)
DEPTNO VARCHAR2(4000)
194

demo
196

SQL> select * from NEW_DATA;
EMPNO SAL DEPTNO
---------- ---------- ----------
1000 5000 20
100X 3550 10
2000 2500 50
7934 4000 20
197
non-numeric
no dept 50
duplicate

SQL> exec dbms_errlog.create_error_log( 'EMP' );
SQL> insert into EMP (empno,sal,deptno)
2 select empno,sal,deptno
3 from NEW_DATA
4 LOG ERRORS REJECT LIMIT UNLIMITED;
1 row created.
198
50

SQL> select ORA_ERR_OPTYP$ op, ORA_ERR_MESG$, EMPNO
2 from ERR$_EMP
OP ORA_ERR_MESG$ EMPNO
-- ------------------------------------------------------------ -----
I ORA-01722: invalid number 100X
I ORA-02291: integrity constraint (SCOTT.FK_DEPTNO) violated 2000
I ORA-00001: unique constraint (SCOTT.PK_EMP) violated 7934
199

favourite:
query blocks
200

C#, C++
203

C#, C++
PL/SQL
204

No comments
205

"C# is self-documenting"
207

good code in any language ...
208

... should self document
209

SQL is no different
210

select emp.*
from emp,
( select trunc(hiredate,'YYYY'), max(empno) empno
from emp
where empno > 0
group by trunc(hiredate,'YYYY') ) x,
( select deptno, avg(sal)
from emp
group by deptno ) y
where x.empno = emp.empno
and y.deptno = emp.deptno

Explain plan

Id | Operation | Name |
----------------------------------------------|
0 | SELECT STATEMENT | |
1 | HASH JOIN | |
2 | TABLE ACCESS BY INDEX ROWID | EMP |
3 | NESTED LOOPS | |
4 | VIEW | |
5 | SORT GROUP BY | |
6 | TABLE ACCESS BY INDEX ROWID| EMP |
7 | INDEX FULL SCAN | E2 |
8 | INDEX RANGE SCAN | E1 |
9 | VIEW | |

explain plan for
select emp.*
from emp,
( select /*+ QB_NAME(lastemp) */
trunc(hiredate,'YYYY'), max(empno) empno
from emp
where empno > 0
( select /*+ QB_NAME(avgsal) */
deptno, avg(sal)
from emp
group by deptno ) y
explain plan for
select emp.*
from emp,
from emp
where empno > 0
deptno, avg(sal)
from emp
group by deptno ) y

explain plan for
select emp.*
from emp,
from emp
where empno > 0
deptno, avg(sal)
from emp
group by deptno ) y

Id | Operation | Name |
----------------------------------------------|
1 | HASH JOIN | |
4 | VIEW | |
9 | VIEW | |
Query Block Name / Alias (identified by operation id):
---------------------------------------------------------
1 - SEL$1
3 - AVGSAL / Y@SEL$1
4 - AVGSAL
5 - AVGSAL / EMP@AVGSAL
6 - SEL$1 / EMP@SEL$1
7 - LASTEMP / X@SEL$1
8 - LASTEMP
9 - LASTEMP / EMP@LASTEMP

query PLAN_TABLE

Id | Operation | Name | Query Block
----------------------------------------------|--------------
1 | HASH JOIN | |
4 | VIEW | |
9 | VIEW | |
SEL$4ADCCA61
SEL$4ADCCA61
AVGSAL
AVGSAL
AVGSAL
AVGSAL
SEL$4ADCCA61
LASTEMP
LASTEMP
LASTEMP
LASTEMP

Runtime statistics as well

SQL> select /*+ gather_plan_statistics */
2 emp.*
3 from emp,
4 ( select /*+ QB_NAME(lastemp) */
5 trunc(hiredate,'YYYY'), max(empno) empno
6 from emp
7 where empno > 0
8 group by trunc(hiredate,'YYYY') ) x,
9 ( select /*+ QB_NAME(avgsal) */
10 deptno, avg(sal)
11 from emp
12 group by deptno ) y
13 where x.empno = emp.empno
14 and y.deptno = emp.deptno
15 /

SQL> select * from
2 table(dbms_xplan.display_cursor(null,null,'IOSTATS LAST +ALIAS'));
-----------------------------------------------------------------------------------
|Id | Operation | Name |Starts | E-Rows | A-Rows |A-Time | Buffers |
-----------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | | 4 |00:00.01 | 21 |
| 1 | HASH JOIN | | 1 | 13 | 4 |00:00.01 | 21 |
| 2 | HASH JOIN | | 1 | 14 | 14 |00:00.01 | 14 |
| 3 | VIEW | | 1 | 3 | 3 |00:00.01 | 7 |
| 4 | HASH GROUP BY | | 1 | 3 | 3 |00:00.01 | 7 |
| 5 | TABLE ACCESS FULL| EMP | 1 | 14 | 14 |00:00.01 | 7 |
| 6 | TABLE ACCESS FULL | EMP | 1 | 14 | 14 |00:00.01 | 7 |
| 7 | VIEW | | 1 | 13 | 4 |00:00.01 | 7 |
| 8 | HASH GROUP BY | | 1 | 13 | 4 |00:00.01 | 7 |
| 9 | TABLE ACCESS FULL | EMP | 1 | 14 | 14 |00:00.01 | 7 |
-----------------------------------------------------------------------------------
Query Block Name / Object Alias (identified by operation id):
-------------------------------------------------------------
1 - SEL$1
3 - AVGSAL / Y@SEL$1
4 - AVGSAL
5 - AVGSAL / EMP@AVGSAL
6 - SEL$1 / EMP@SEL$1
7 - LASTEMP / X@SEL$1
8 - LASTEMP
9 - LASTEMP / EMP@LASTEMP

SQL> alter session set
2 events = '10053 trace name context forever, level 1';
Session altered.
223

**************************
Query transformations (QT)
**************************
CBQT: Validity checks passed for 7jpzpr2475cqw.
CSE: Sub-expression elimination in query block SEL$1 (#0)
*************************
Common Subexpression elimination (CSE)
*************************
CSE: CSE not performed on query block LAST_EMP(#0).
CSE: Sub-expression elimination in query block AVG_SAL (#0)
CSE: CSE not performed on query block AV_SAL (#0).
CSE: CSE not performed on query block SEL$1 (#0).
***************************
Order-by elimination (OBYE)
***************************
OBYE: Considering Order-by Elimination from view SEL$1 (#0)
224

assist with hints
225

select
/*+ QB_NAME(top)
INDEX(@yr_hire emp (empno))
FULL(@av_sal emp)
*/
emp.*
from emp,
( select /*+ QB_NAME(YR_HIRE) */
from emp
where empno > 0
( select /*+ QB_NAME(AV_SAL) */
deptno, avg(sal)
from emp
group by deptno ) y
226

Help the next person

It’s probably you

Favourite:
subquery factoring
229
part 2

first principles
230

SQL> select rpad(' ',level)||ename,
2 from emp
3 start with mgr is null
4 connect by prior empno = mgr
ENAME
---------------------------
KING
BLAKE
JAMES
ALLEN
WARD
CLARK
MILLER
231

SQL> select empno, ename, mgr
2 from emp
3 where mgr is null;
EMPNO ENAME MGR
---------- -------------------- ----------
7839 KING
232

SQL> select e2.empno, e2.ename, e2.mgr
2 from emp e2,
3 ( select empno, mgr
4 from emp
5 where mgr is null ) inner
6 where e2.mgr = inner.empno;
EMPNO ENAME MGR
---------- -------------------- ----------
7566 JONES 7839
7698 BLAKE 7839
7782 CLARK 7839
233

2 from emp e3,
3 ( select e2.empno, e2.ename, e2.mgr
4 from emp e2,
6 from emp
8 where e2.mgr = inner.empno ) inner
EMPNO ENAME MGR
---------- -------------------- ----------
7902 FORD 7566
7788 SCOTT 7566
7900 JAMES 7698
7844 TURNER 7698
7654 MARTIN 7698
7521 WARD 7698
7934 MILLER 7782
234

2 from emp e4,
4 from emp e3,
6 from emp e2,
8 from emp
EMPNO ENAME MGR
---------- -------------------- ----------
7876 ADAMS 7788
recursive...
235

WITH can be recursive
237

SQL> with EACH_LEVEL (empno, name, mgr) as
2 ( --
3 -- start with
4 --
5 select empno, ename, mgr
6 from emp
7 where mgr is null
8 --
9 -- connect by
10 --
11 union all
12 select emp.empno, emp.ename, emp.mgr
13 from emp, EACH_LEVEL
14 where emp.mgr = each_level.empno
15 )
16 select *
17 from each_level;
238

EMPNO NAME MGR
---------- --------------- ----------
7839 KING
7566 JONES 7839
7698 BLAKE 7839
7782 CLARK 7839
7499 ALLEN 7698
7521 WARD 7698
7654 MARTIN 7698
7788 SCOTT 7566
7844 TURNER 7698
7900 JAMES 7698
7902 FORD 7566
7934 MILLER 7782
7369 SMITH 7902
7876 ADAMS 7788
239

two part structure
240

with RECURSIVE_WITH (c1,c2,c3) as
(
<starting/entry point>
union all
<recursive relationship>
)
select ...
from RECURSIVE_WITH
241

you control pseudo-functions
242

SQL> with each_level (empno, name, mgr, rlevel) as
2 ( select empno, ename, mgr, 1 rlevel
3 from emp
4 where mgr is null
5 union all
6 select emp.empno, emp.ename, emp.mgr, rlevel+1
7 from emp, each_level
9 )
10 select * from each_level;
EMPNO NAME MGR RLEVEL
---------- --------------- ---------- ----------
7839 KING 1
7566 JONES 7839 2
7698 BLAKE 7839 2
7782 CLARK 7839 2
7499 ALLEN 7698 3
<etc>
243

SQL> with each_level (empno, name, mgr, level) as
2 ( select empno, ename, mgr, 1 level
3 from emp
4 where mgr is null
5 union all
6 select emp.empno, emp.ename, emp.mgr, level+1
9 )
10 select empno, name, mgr, level from each_level;
with each_level (empno, name, mgr, level) as
*
ERROR at line 1:
ORA-00904: : invalid identifier
244

SQL> with each_level (empno, name, mgr, rlevel) as
2 ( select empno, ename, mgr, 1 rlevel
3 from emp
4 where mgr is null
5 union all
6 select emp.empno, emp.ename, emp.mgr, rlevel+1
9 )
10 select empno, name, mgr, rlevel as "LEVEL"
11 from each_level;
245

SQL> with each_level (empno, name, mgr, padding) as
2 ( select empno, ename, mgr, '' padding
3 from emp
4 where mgr is null
5 union all
6 select e.empno, e.ename, e.mgr, padding || ' '
7 from emp e, each_level
8 where e.mgr = each_level.empno
9 )
10 select empno, padding||name name
11 from each_level;
ERROR:
ORA-01489: result of string concatenation is too long
246

SQL> with each_level (empno, name, mgr, padding) as
2 ( select empno, ename, mgr,
3 cast('' as varchar2(100)) padding
4 from emp
5 where mgr is null
6 union all
7 select e.empno, e.ename, e.mgr, padding || ' '
10 )
11 select empno, padding||name name
12 from each_level;
EMPNO NAME
---------- --------------------------------
7839 KING
7566 JONES
...
247

SQL> with each_level (empno, name) as
2 ( select empno, ename from emp
3 where mgr is null
4 union all
5 select e.empno,
6 each_level.name||'-'||e.ename
9 )
10 select empno, name from each_level;
EMPNO NAME
---------- --------------------------------
7839 KING
7566 KING-JONES
7698 KING-BLAKE
7782 KING-CLARK
7499 KING-BLAKE-ALLEN
7521 KING-BLAKE-WARD
<etc>
248

some nice touches...
249

SQL> with each_level (empno, name, hiredate, mgr) as
2 ( ... )
9 SEARCH BREADTH FIRST BY HIREDATE SET IDX
10 select name, hiredate, idx from each_level;
NAME HIREDATE IDX
-------------------------------- --------- ----------
KING 17-NOV-81 1
KING-JONES 02-APR-81 2
KING-BLAKE 01-MAY-81 3
KING-CLARK 09-JUN-81 4
KING-BLAKE-ALLEN 20-FEB-81 5
KING-BLAKE-WARD 22-FEB-81 6
[snip]
KING-JONES-FORD-SMITH 17-DEC-80 13
KING-JONES-SCOTT-ADAMS 23-MAY-87 14
250

SQL> with each_level (empno, name, hiredate, mgr) as
2 ( ... )
9 SEARCH DEPTH FIRST BY HIREDATE SET IDX
10 select name, hiredate, idx from each_level;
NAME HIREDATE IDX
-------------------------------- --------- ----------
KING 17-NOV-81 1
KING-JONES 02-APR-81 2
KING-JONES-FORD 03-DEC-81 3
KING-JONES-FORD-SMITH 17-DEC-80 4
KING-JONES-SCOTT 19-APR-87 5
KING-JONES-SCOTT-ADAMS 23-MAY-87 6
KING-BLAKE 01-MAY-81 7
KING-BLAKE-ALLEN 20-FEB-81 8
etc
251

get used to it .....
ANSI
252

Favourite:
sql transposition
253

rows to columns, colums to rows
254

"I need sales by product
for each quarter....now"
255

SQL> select product,
2 trunc(txn_date,'Q') mth, sum(quantity) total
3 from SALES
4 group by product,trunc(txn_date,'Q')
5 order by 1,2;
PRODUCT MTH TOTAL
-------------------- --- ----------
CHAINSAW JAN 251473
CHAINSAW APR 254830
CHAINSAW JUL 251994
CHAINSAW OCT 243748
HAMMER JAN 249889
HAMMER APR 256566
HAMMER JUL 252992
HAMMER OCT 249104
SCREW DRIVER JAN 245988
SCREW DRIVER APR 249219
SCREW DRIVER JUL 252128
256

"That’s junk...surely you know
I wanted it ACROSS the page"
257

PIVOT clause
260

SQL> select *
2 from (select product,
3 trunc(txn_date,'Q') mth,
4 quantity
5 from sales )
6 pivot( sum(quantity) for mth in
7 ( 'JAN','APR','JUL','OCT' ) )
11 order by 1
12 /
PRODUCT 'JAN' 'APR' 'JUL' 'OCT'
-------------------- ---------- ---------- ---------- ----------
CHAINSAW 251473 254830 251994 243748
HAMMER 249889 256566 252992 249104
SCREW DRIVER 245988 249219 252128 244721
SPADE 242434 254090 259613 248428
WHEEL BARROW 243899 249327 252296 254137
261

"nah...make it go DOWN the page
262

SQL> create table PIVOTED_SALES as select *
2 from (select product,
3 trunc(txn_date,'Q') mth,
4 quantity
5 from sales )
6 pivot( sum(quantity) for mth in
7 ( 'JAN',
8 'APR',
9 'JUL',
10 'OCT') )
11 order by 1
12 /
Table created.
263

UNPIVOT clause
264

SQL> desc PIVOTED_SALES
Name Null? Type
----------------------------- -------- -------------
PRODUCT VARCHAR2(20)
Q1 NUMBER
Q2 NUMBER
Q3 NUMBER
Q4 NUMBER
265

SQL> select *
2 from PIVOTED_SALES
3 UNPIVOT
4 ( quantity for quarter in (Q1,Q2,Q3,Q4) )
5 /
PRODUCT QUARTER QUANTITY
-------------------- ------- ----------
CHAINSAW Q1 251473
CHAINSAW Q2 254830
CHAINSAW Q3 251994
CHAINSAW Q4 243748
HAMMER Q1 249889
HAMMER Q2 256566
HAMMER Q3 252992
HAMMER Q4 249104
SCREW DRIVER Q1 245988
...
column values
become "quantity"
column names
become "quarter"
266

elements must be known in advance
267

Wrap up

lots not covered today

why talk about SQL
(reason 4)
270

Life is too short
271
(look away now if you are squeamish)

import java.sql.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.accessibility.*;
import com.sun.java.accessibility.util.*;
public AssistiveExample extends JPanel
implements MouseMotionListener, ActionListener,
GUIInitializedListener {
Timer timer;
static JFrame frame;
JLabel nameLabel = new JLabel();
JLabel descriptionLabel = new JLabel();
JLabel tableLabel = new JLabel();
JCheckBox selectionCheckBox = new JCheckBox("Selection",
false);
JCheckBox textCheckBox = new JCheckBox("Text", false);
JCheckBox valueCheckBox = new JCheckBox("Value", false);
JCheckBox componentCheckBox = new JCheckBox("Component",
false);
JCheckBox actionCheckBox = new JCheckBox("Action", false);
JCheckBox hypertextCheckBox = new JCheckBox("Hypertext",
false);
JCheckBox iconCheckBox = new JCheckBox("Icon", false);
JCheckBox tableCheckBox = new JCheckBox("Table", false);
JCheckBox editableTextCheckBox = new JCheckBox("EditableText",
false);
JLabel classLabel = new JLabel();
JLabel parentLabel = new JLabel();
JLabel relationLabel = new JLabel();

SQL is faster
274

SQL is easier
275

SQL is more exciting
277

Connor McDonaldORA-03113

Creative Commons Image Resources
https://commons.wikimedia.org/wiki/File:Horse_Race_Finish_Line_(11888565543).jpg
https://pixabay.com/en/iphone-iphone-6-apple-flat-762044/
https://pixabay.com/en/curve-return-pass-road-384406/
https://pixabay.com/en/high-five-figure-man-blue-150911/
https://pixabay.com/en/joker-jester-card-playing-card-164030/
https://commons.wikimedia.org/wiki/File:2008-08-19_Flat_tire.jpg
https://upload.wikimedia.org/wikipedia/commons/4/4d/3DCrystal_ball.png

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