Using Subqueries with the EXISTS Operators in SQL Server

Q

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

✍: FYIcenter.com

A

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 fyi_links table that there are rows existing in the fyi_rates table with the same id.

SELECT id, url, tag, YEAR(created) As year 
   FROM fyi_links WHERE EXISTS (
   SELECT * FROM fyi_rates 
   WHERE fyi_rates.id = fyi_links.id)
GO
id      url                     tag     Year
101     dev.fyicenter.com       DEV     2006
102     dba.fyicenter.com       DBA     2007
103     sqa.fyicenter.com       SQA     2007

Note that the subquery uses columns from the source table of the outer query.

 

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2016-10-29, 723👍, 0💬