>>>I'll try later - busy with work right now. I tried on the tables I had in my test database (in SQL Server).
>>
>>Ok I just tried for you:
>>

>                                                    t6   t5   t4   t3   t2   t1
>>Client processing time         0    0    0    0    0   16 
>>Total execution time        2328 2296 3046 2250 2328 5937 
>>Wait time on server replies 2328 2296 3046 2250 2328 5921 
>>

>>
>>Two passes. t1,4 (LEFT), t2,5 (NOT IN), t3, 6 (Exists).
>>Cetin
>
>In your tests performance of the LEFT JOIN seems to be much worse than others. What are tables metrics and how many records did you get as a result of a query? Also, did you discharge the results or not?

Yes as I told you before it was the slowest. Metric is simple. 2 million records table created, and copied onto another (structure was as simple as it can be, an ID plus a varchar data field. With a more complex structure it is likely it would be much slower). Then a few more records are added to one of them. Index created on join field.
Cetin