How To Use Subqueries with the EXISTS Operator
Q
How To Use Subqueries with the EXISTS Operator? - MySQL FAQs - SQL SELECT Statements with JOIN and Subqueries
✍: 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.
mysql> SELECT id, url, tag, YEAR(created) As year FROM fyi_links WHERE EXISTS ( SELECT * FROM fyi_rates WHERE fyi_rates.id = fyi_links.id); +-----+-------------------+------+------+ | id | url | tag | year | +-----+-------------------+------+------+ | 101 | dev.fyicenter.com | DEV | 2006 | | 102 | dba.fyicenter.com | DBA | 2006 | | 103 | sqa.fyicenter.com | SQA | 2006 | +-----+-------------------+------+------+ 3 rows in set (0.00 sec)
2007-05-11, 6404👍, 0💬
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