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 !!?

Answers were Sorted based on User's Feedback



Can any one tell me how to increase the performance of a sql query ie what are the performance tip..

Answer / manoj

1.
Use proper sequence of tables in from clause
i.e.
the table have more common column must in last
in form clause bcoz on firing of query engine link
last table in form clause
2.
Use "Exist" clause instead of "Not in"
Bcoz it return only true/false(boolean)

3.
Use "Hint" if Required

Is This Answer Correct ?    6 Yes 0 No

Can any one tell me how to increase the performance of a sql query ie what are the performance tip..

Answer / sathishrpillai

Hii..
for optimization of sql query
1.don't use select * from,choose particular fields itself
2.don't use both OR ,AND in same query
3.Minimise the use of aggreagate functions such sum,count
4.don't link unneccessary tables

Is This Answer Correct ?    5 Yes 2 No

Can any one tell me how to increase the performance of a sql query ie what are the performance tip..

Answer / 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

Is This Answer Correct ?    0 Yes 0 No

Post New Answer

More SQL PLSQL Interview Questions

Why truncate is used in sql?

0 Answers  


What is flag in sql?

0 Answers  


What are the advantages and disadvantages, compared to the standard SQL and SQL*plus ?

2 Answers  


What is use of package in pl sql?

0 Answers  


what is the difference between nested subquery and correlated subquery?

0 Answers  






Why triggers are used?

0 Answers  


What is an exception in PL/SQL? What are the two types of exceptions?

0 Answers  


What is trigger in sql and its types?

0 Answers  


What is program debugging?

0 Answers  


Delete the emps whose salaries are lowest sals of their own dept.

5 Answers  


How to write html code in pl sql?

0 Answers  


what is sql profiler

2 Answers   Fidelity,


Categories