MS SQL Server Interview Question:

How To Use Subqueries with the EXISTS Operators in MS SQL Server?

Submitted by: Administrator

A subquery can be used with the EXISTS operator as "EXISTS (subquery)", which returns true if the subquery returns one or more rows. The following statement is a good example of "EXISTS (subquery)". It returns rows from ggl_links table that there are rows existing in the ggl_rates table with the same id.

SELECT id, url, tag, YEAR(created) As year
FROM ggl_links WHERE EXISTS (
SELECT * FROM ggl_rates
WHERE ggl_rates.id = ggl_links.id)
GO
<pre>
id url tag Year
101 www.globalguideline.com main 2006
102 www.globalguideline.com/html DBA 2007
103 www.globalguideline.com/sql SQL 2007
</pre>
Note that the subquery uses columns from the source table of the outer query.
Submitted by: Administrator