Whats wrong with this update statement

Please start any new threads on our new site at https://forums.sqlteam.com. We've got lots of great SQL Server experts to answer whatever question you can come up with.

All Forums

SQL Server 2005 Forums

Transact-SQL (2005)

Whats wrong with this update statement

Author

Topic

mary_itohan
Posting Yak Master

191 Posts

Posted - 2008-09-23 : 13:54:40

Hello,
Am working on a billing system and guarding against negative billing.

What is wrong with this


--update table
if ((update tbl_credits set credits = (credits - @billing) where username = @user) < 0)
-- if results are less than 0. ie negative. Update to 0
begin
update tbl_credits set credits = 0 where username = @user
end

I get this error

Msg 102, Level 15, State 1, Procedure My_billing, Line 209
Incorrect syntax near 'tbl_credits'.

_____________________

Yes O !

visakh16
Very Important crosS Applying yaK Herder

52326 Posts

Posted - 2008-09-23 : 14:03:13

what you want is this

update tbl_credits 
set credits = case when (credits - @billing)<0 then 0 else  (credits - @billing) end
where username = @user

mary_itohan
Posting Yak Master

191 Posts

Posted - 2008-09-23 : 14:25:33

Cool. Thanks

Is it possible to get the value of the previous credits during the transaction ? ie

Merge the two codes below into one ???


set @present_credits = (select credits from tbl_credits where username = @user)

update tbl_credits 
set credits = case when (credits - @billing)<0 then 0 else  (credits - @billing) end
where username = @user

_____________________

Yes O !

visakh16
Very Important crosS Applying yaK Herder

52326 Posts

Posted - 2008-09-23 : 14:28:58

yup you can

update tbl_credits 
set credits = case when (credits - @billing)<0 then 0 else  (credits - @billing) end,
@present_credits =credits
where username = @user

mary_itohan
Posting Yak Master

191 Posts

Posted - 2008-09-23 : 15:52:00

great.

Thanks

_____________________

Yes O !

mary_itohan
Posting Yak Master

191 Posts

Posted - 2008-09-23 : 18:17:12

One last question.

Is it possible to assign the credits after this transaction to a variable ? Or i have to run a seperate select command ie

update tbl_credits
set credits = case when (credits - @billing)<0 then 0 else (credits - @billing) end,
@present_credits =credits
where username = @user

set @credits_after = (select credits from tbl_credits where username = @user)

_____________________

Yes O !

visakh16
Very Important crosS Applying yaK Herder

52326 Posts

Posted - 2008-09-24 : 01:41:23

try like this

update tbl_credits 
set @credits_after =credits = case when (credits - @billing)<0 then 0 else (credits - @billing) end,
@present_credits =credits
where username = @user

Subscribe to SQLTeam.com

SQLTeam.com Articles via RSS

SQLTeam.com Weblog via RSS

- Advertisement -

Resources