SQL Subquery

Syntax - Subquery
SELECT Statement WHERE ColumnName [Comparison Operator] (SELECT Statement / Values)
Results of one Sql query or Sql statement as the input for another Select query, Insert Into query, Insert From query, Update query and Delete query.
You also can use the result of Subquery as a search condition for using in the IN( ) function or EXISTS operator.

Comparison Operator such as =, >, <, >=, <=, LIKE, IN

Below is example for SQL UNION

Company	Sales($)	Website
Sql Traniner	2500	http://www.sqltutorials.blogspot.com
BeautyCentury	3000	http://beautycentury.blogspot.com
TravelYourself	2800	http://travelyourself.blogspot.com

Table1

Sales	Website
2900	http://www.sqltutorials.blogspot.com
3000	http://beautycentury.blogspot.com
2800	http://travelyourself.blogspot.com

Table2


SQL Subquery Statement

SELECT * FROM TABLE1 WHERE sales in (SELECT Sales FROM TABLE2)
Result

BeautyCentury	3000	http://beautycentury.blogspot.com
TravelYourself	2800	http://travelyourself.blogspot.com

SELECT * FROM TABLE1 WHERE sales LIKE (SELECT Sales FROM TABLE2 WHERE Sales <2900)>
Result

TravelYourself

2800

http://travelyourself.blogspot.com

SELECT * FROM TABLE1where sales > (SELECT Sales FROM TABLE2 WHERE Sales <2900)
Result

BeautyCentury

3000

http://beautycentury.blogspot.com