SQL Question 
Author Message
 SQL Question

Does referencing a column in the right-hand side of the = in an
UPDATE....SET statement always refer to the value before the update?

Does it depend on the implementation?  Is this addressed in the ANSI SQL

Here's what I mean......

UPDATE some_table
SET    first_value = first_value - (something - something_else)
           second_value = first_value - (something - something_else)
WHERE whatever.........

My intent is to end up with second_value being equal to first_value.  I
tested on Informix 7.31 and Oracle (I didn't pay attention to the
version) and it worked as I expected on both.

Sat, 05 Jun 2004 12:50:34 GMT
 SQL Question

Yes, this is standard. The right hand side is completely computed before
the assignment happens.

Serge Rielau
DB2 UDB SQL Compiler Development
IBM Software Lab, Canada

Sat, 05 Jun 2004 23:58:07 GMT
 [ 2 post ] 

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