About SubQueries

 

 

Subquery often is an alternative for joins. Also you can use both in your queries. Whenever you hate joins, you can go with Subquery. Since in some places (based on the data on the table) subquery performs "better" than joins.AFAIK, this the one case we need subquery.

 

 

It is based on the data on hand. In my experience, i found that in some places Subqueries are works better than joins. In some place vice-versa. So it purely depends on your data.

 

Here is some useful links for this debate:

 

 

 

 

Hope this helps!

Hello Gaurav,  

 

 

subquery is a query within a query. You can create subqueries within your SQL statements. These subqueries can reside in the WHERE clause, the FROM clause, or the SELECT clause.

More details check below links

 

http://www.techonthenet.com/sql_server/subqueries.php

 

https://www.simple-talk.com/sql/sql-training/subqueries-in-sql-server/

 

http://beginner-sql-tutorial.com/sql-subquery.htm 

 

 

 

Joins and subqueries are both used to combine data from different tables into a single result. They share many similarities and differences. 

 

more details refer below links

 

http://www.essentialsql.com/what-is-the-difference-between-a-join-and-subquery/

 

http://www.exacthelp.com/2012/10/subquery-vs-inner-join-which-one-is.html

 

http://blog.sqlauthority.com/2010/06/06/sql-server-subquery-or-join-various-options-sql-server-engine-knows-the-best/ 

http://www.tutorialspoint.com/sql/sql-sub-queries.htm

 

https://technet.microsoft.com/en-us/library/ms189575(v=sql.105).aspx