23.03.11 11:17, Adarsh Sharma написав(ла):
I think it is very much faster but I don't understand the query :
explain select distinct(b) from t1,t2 where t1.b >t2.d union all select distinct(b) from t1,t2 where t1.b <t2.d;
I don't understand it too. What are you trying to get? Is it
select distinct(b) from t1 where b > (select min(d) from t2)
or b < (select max(d) from t2)
?
Can you explain in words, not SQL, what do you expect do retrieve?
Best regards, Vitalii Tymchyshyn