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PHP MySQL update supquery
Posted on 2011-02-24
I'm sure this is a pretty simple question, but I can't think of a solution at the moment. I'm trying to update a decimal value, based on the current value of the field.
I want to reduce the amount in the field by the amount in a variable... something like this...
"currentrequest" is the current field... So, basically I want to update current request to be it's current value minus 100.00.
I've tried using a select subquery in there, and it tells me that I can't select the same table...
The error I receive is: "You can't specify target table 'budget' for update in FROM clause".
Thanks for any shoves in the right direction!
I want to reduce the amount in the field by the amount in a variable... something like this...
"currentrequest" is the current field... So, basically I want to update current request to be it's current value minus 100.00.
I've tried using a select subquery in there, and it tells me that I can't select the same table...
The error I receive is: "You can't specify target table 'budget' for update in FROM clause".
Thanks for any shoves in the right direction!
$reqAmt=100.00;
$removeFromBudget=@mysql_query("
UPDATE budget
SET currentrequest='currentrequest-".$reqAmt."'
WHERE acct='".$acctNum."' LIMIT 1");
[X]
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7 Comments
Just found the answer... Posting in case anyone else needs it...
$removeFromBudget=@mysql_query("
UPDATE budget
SET currentrequest=((SELECT currentrequest)-".$reqAmt.")
WHERE acct='".$acctNum."' LIMIT 1");
That is the whole query... The sub query is in the SET currentrequest..... line...
Are you not seeing that line? Or am I describing it incorrectly?
Are you not seeing that line? Or am I describing it incorrectly?
Interesting... I was always taught that anything like that inside another query would be considered a subquery. Would you know what it should be called, then?
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