SQL Tuning

Sql Statements are used to retrieve data from the database. We can get same results by writing different sql queries. But use of the best query is important when performance is considered. So you need to sql query tuning based on the requirement. Here is the list of queries which we use reqularly and how these sql queries can be optimized for better performance.

SQL Tuning/SQL Optimization Techniques:

1) The sql query becomes faster if you use the actual columns names in SELECT statement instead of than '*'.

For Example: Write the query as

SELECT id, first_name, last_name, age, subject FROM student_details;

Instead of:

SELECT * FROM student_details;9) To store large binary objects, first place them in the file system and add the file path in the database.

8) Use DECODE to avoid the scanning of same rows or joining the same table repetitively. DECODE can also be made used in place of GROUP BY or ORDER BY clause. 
For Example: Write the query as

SELECT id FROM employee 
WHERE name LIKE 'Ramesh%' 
and location = 'Bangalore';

Instead of:

SELECT DECODE(location,'Bangalore',id,NULL) id FROM employee 
WHERE name LIKE 'Ramesh%';

9) To store large binary objects, first place them in the file system and add the file path in the database.

10) To write queries which provide efficient performance follow the general SQL standard rules.

a) Use single case for all SQL verbs
b) Begin all SQL verbs on a new line
c) Separate all words with a single space
d) Right or left aligning verbs within the initial SQL verb