| SUBQUERY [message #372994] |
Wed, 21 March 2001 11:42  |
II
Messages: 1
Registered: March 2001
|
Junior Member |
|
|
WHAT IS THE DIFFERENT BETWEEN SIMPLE SUBQUERY,COMPLEX SUBQUERY,AND CO-RELATED SUBQUERY?
THANKS!
|
|
|
|
| Re: SUBQUERY [message #373033 is a reply to message #372994] |
Fri, 23 March 2001 11:40  |
ramu
Messages: 82
Registered: February 2001
|
Member |
|
|
Simple subquery is one the sub query used to filter the main query..
For example:
SELECT *FROM EMP WHERE DEPTNO=(SELECT DEPTNO FROM DEPT WHERE DNAME='ACCOUNTS';
Here to select all the values from emp the condition Deptno having the values filtered from the DEPT table;
Complex Subquery may be like the subquery again use the filtering condition..
Corelated subquery is one that the subquery refers to main..
For example:
SELECT SAL FROM EMP X WHERE &N=(SELECT COUNT(SAL) FROM EMP WHERE SAL>=X.SAL)
Here the main query has a reference in the subquery..
I have only this idea.. If any one give suggession I will accept that..
Thanks..
Ramu..
|
|
|
|
] 
Blog
Search
Help
Members
Register
Login
Home
