SQL EXISTS

Using a subquery to test for the existence of rows. If it Exists Operators return a row, then the outer query proceeds. If not, the outer query does not execute or return any result or row.

Below is Example for SQL EXISTS
 

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 EXISTS Statement

SELECT * FROM TABLE1 WHERE EXISTS(SELECT * FROM TABLE2)
Result

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

- We also can using the EXISTS in IF...ELSE Statement to checking the existence of a row or value.
- If IF...ELSE return true, it will return the result of Sql statement inside the BEGIN and END.

IF EXISTS(SELECT * FROM TABLE1 WHERE Company='TravelYourself')
BEGIN
SELECT * FROM TABLE1 WHERE Company='TravelYourself'
END

Result  

TravelYourself

2800

http://travelyourself.blogspot.com

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