>>>It's here: using '==' is much slower than '='.
>>
>>Depending on the ANSI setting, no?
>
>You know, the only way to have definite opinion about optimization is to test it. I just tested again and see that '=' is always better than "==", and Set ANSI OFF is always better than ON (in any combination).
>I will appreciate any thoughts about it.

From the help on ANSI :

SET ANSI determines whether the shorter of two strings is padded with blanks when a SQL string comparison is made. SET ANSI has no effect on the == operator; when you use the == operator, the shorter string is always padded with blanks for the comparison.

'Tommy' = 'Tom'
The result is false (.F.) if SET ANSI is ON.

'Tommy' = 'Tom'
The result is true (.T.) when SET ANSI is OFF.

'Tommy' == 'Tom' returns false.

So I guess it's better to set ANSI to ON to have proper results
with the '=' operator.

Claude.