The document discusses updating a sequence number in one table (TBUSERDTL) to match the sequence number from another table (SEQUENCENOUPDATE) where the entity ID (eid) matches between the two tables. It provides two solutions for rewriting an SQL update statement using an inner join to work in Oracle instead of SQL Server. The second solution is noted to improve performance over the first by using an EXISTS clause instead of an IN clause.

1. SQL Problem #5
Update statement using inner join
I have two tables TBUSERDTL TL and
SEQUENCENOUPDATE SU. I need to update the
TL.sequence_nu to the SU.sequence_nu. The
TL.eid is currently same as SU.eid so I am joining
on this column.

2. The following update statement works fine in SQL Server:
UPDATE TBUSERDTL TL
SET SEQUENCE= SU.SEQUENCE_NU
FROM TABLE TBUSERDTL
INNER JOIN SEQUENCENOUPDATE SU
ON EID = SU.EID
THIS WILL NOT WORK IN ORACLE.

3. How do I rewrite in Oracle
Solution 1:
update tbuserdtl
set sequence_nu =(select sequence_nu
from sequencenoupdate su
where tbuserdtl.eid = su.eid)
where eid in (select eid from sequencenoupdate)
Tbuserdtl and Sequencenoupdate. Updating sequence no
in detail table from the sequencenoupdate table where eid
matched.

4. Improve Performance
Solution 2:
update tbuserdtl tl
set sequence_nu =(select su.sequence_nu
from sequencenoupdate su
where tbuserdtl.eid = su.eid)
where exists (select *
from sequencenoupdate su
where su.eid = tl.eid)