> in a 'SELECT', does postgres read the 'WHERE' condition from left to right.
PostgreSQL (SQL in general?) does NOT define evaluation order (unlike
programming languages like C).
> for example
> 1) select ... where a and b;
> 2) select ... where b and a;
>
> 1 and 2 will use the same cpu time or not ?
Depends on the problem.
In theory the optimizer should find the best evaluation order
after analyzing a and b.
Bye, Chris.