Portal | Manuals | References | Downloads | Info | Programs | JCLs | Master the Mainframes
IBM Mainframe Computers Forums Index
 
Register
 
IBM Mainframe Computers Forums Index Mainframe: Search IBM Mainframe Forum: FAQ Memberlist Usergroups Profile Log in to check your private messages Log in
 

 

update SQL with sub-query

 
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> DB2
View previous topic :: :: View next topic  
Author Message
tzeche

New User


Joined: 08 Jun 2007
Posts: 2
Location: Philippines

PostPosted: Wed Mar 04, 2015 1:30 pm    Post subject: update SQL with sub-query
Reply with quote

I have an update query below and need to convert it to test first whether the sub-query (SELECT MAX(COL_A) FROM TABLE2 WHERE COL_B = TB1.COL_2) returns a NULL value

UPDATE TABLE1 TB1
SET COL_1 = (SELECT MAX(COL_A) FROM TABLE2
WHERE COL_B = TB1.COL_2)


If the sub-query returns a NULL then COL_1 will retain it's existing value but if not then COL_1 will be updated with the value returned from the sub-query

Please help me, I can't seem to get it right.

Do I need to use CASE? How?
Back to top
View user's profile Send private message

GuyC

Senior Member


Joined: 11 Aug 2009
Posts: 1278
Location: Belgium

PostPosted: Wed Mar 04, 2015 5:14 pm    Post subject:
Reply with quote

untested:
Quote:
UPDATE TABLE1 TB1
SET COL_1 = (SELECT MAX(COL_A) FROM TABLE2
WHERE COL_B = TB1.COL_2)
where exists(SELECT COL_A FROM TABLE2
WHERE COL_B = TB1.COL_2 and col_A is not null)
Back to top
View user's profile Send private message
tzeche

New User


Joined: 08 Jun 2007
Posts: 2
Location: Philippines

PostPosted: Thu Mar 05, 2015 11:04 pm    Post subject:
Reply with quote

Thank you GuyC! it worked fine!
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> DB2 All times are GMT + 6 Hours
Page 1 of 1

 

Search our Forum:

Similar Topics
Topic Author Forum Replies Posted
No new posts SQL query not working in Cobol program. CuriousMainframer COBOL Programming 1 Wed Feb 22, 2017 5:56 pm
No new posts Omegamon for DB2 query ashek15 DB2 0 Wed Feb 15, 2017 11:25 am
No new posts Query on DB2 WLM stored procedures ashek15 DB2 8 Sun Feb 12, 2017 11:13 pm
No new posts GETMAIN/FREEMAIN query Suja.Sai CICS 9 Tue Jan 31, 2017 12:01 pm
No new posts Join in SQL Query vickey_dw DB2 2 Tue Jan 17, 2017 12:15 am


Facebook
Back to Top
 
Mainframe Wiki | Forum Rules | Bookmarks | Subscriptions | FAQ | Tutorials | Contact Us