Post reply

WHERE Clause with OR operator: are both statements execd?

  • March 19, 2004 at 5:26 am

    #107459

    I could not find this in BOL: in a query like

    SELECT col FROM table WHERE cond_1 OR cond_2.

    When cond_1 is TRUE will SQL Server check if cond_2 is TRUE? And if this is correct, is there a way to prevent this?

    Thank you for your attention,

    Gerry

    Dutch Anti-RBAR League

  • March 19, 2004 at 5:42 am

    #499479

    It should only evaluate to the first true condition in an OR chain.

  • March 19, 2004 at 8:23 am

    #499509

    I've had BAD experiences with this.

    If an index is to be used for one of the columns on the where clause, sometimes that expression is evaluated FIRST so the chain evaluation order is not actually from left to right 

     

     

     


    * Noel

Viewing 3 posts - 1 through 2 (of 2 total)

You must be logged in to reply to this topic. Login to reply