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Can any one tell me how to increase the performance of a
sql query ie what are the performance tips in creating or
writing a sql query !!?
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Answer Posted / hutashan
use Inline view to eleminate large number of rows
Avoid implicit datatype conversion
Avoid using function on an indexed column
Avoid comparing column value with NULL
Outer Join
Use OR carefully
Do not use outer join unless absolutely necessary. Degree
of optimizing outer join permutation is VERY LIMITED
Instead: Consider using default values in the base table to
avoid outer join
Do not outer join to a view. This typically results in a
non-mergable view execution plan
Always use NOT EXISTS instead of NOT IN
Remove DISTINCT keyword from SELECT if UNION is used
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