On 19/08/2009 11:26 AM, Simon Slavin wrote: > DRH's post trumps mine, of course. I'm surprised to find that > brackets are optimised out of WHERE evaluations.
Why? In the OP's example (all AND operators) the parentheses are redundant. In SQL, AND and OR are not guaranteed to be short-circuited; both operands may be evaluated. In a case like (a+b)*(c+d) the parentheses are necessary otherwise a+b*c+d would be interpreted as a+(b*c)+d. In parsing any expression in any language, one would expect unless documented otherwise that there was no other guarantee of order of evaluation -- if your expression has side-effects you are on your own. Generally parentheses are ignored immediately their purpose (overriding operator precedence) has been fulfilled. _______________________________________________ sqlite-users mailing list [email protected] http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
