UPDATE statement wrapped in an IF EXISTS block
- by formica
I'm trying to write a DML script that updates a column but I wanted to make sure the column existed first so I wrapped it in a IF EXISTS block
IF EXISTS(SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME='Client' AND COLUMN_NAME='IsClarityEnabled')
BEGIN
UPDATE Client SET IsClarityEnabled = 1 WHERE ClientID = 21
END
So the weirdness is that it tries to execute the update even if it fails the condition. So column doesn't exist and the UPDATE statement runs and I get an error. Why?
Even stranger is that this does work:
IF EXISTS(SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME='Client' AND COLUMN_NAME='IsClarityEnabled')
BEGIN
EXEC('UPDATE Client SET IsClarityEnabled = 1 WHERE ClientID = 21')
END
Is there something special about an UPDATE command that causes it to behave this way?
