Is JOIN between tables is better than using IN operator?
SOLUTION:
The query optimizer is better when using JOIN and not IN operator. When using IN operator the following query:
Select *
from T1
where x in
(select
y from T2)
is typically processed as:
Select *
from T1, (select distinct y from t2) t2
where t1.x = t2.y
The sub query is evaluated, distanced, indexed (or hashed or sorted) and then joined to the original table.
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