![]() When you use a subquery in the FROM clause, the result set returned from a subquery is used as a temporary table. Try It Out MySQL subquery in the FROM clause Orders) Code language: SQL (Structured Query Language) ( sql ) ![]() See the following customers and orders tables:įor example, you can use a subquery with NOT IN operator to find the customers who have not placed any orders as follows: SELECT If a subquery returns more than one value, you can use other operators such as IN or NOT IN operator in the WHERE clause. MySQL subquery with IN and NOT IN operators Then, select the payments that are greater than the average payment returned by the subquery in the outer query.First, get the average payment by using a subquery.Payments) Code language: SQL (Structured Query Language) ( sql ) You can use comparison operators e.g., =, >, ), greater than or equal to (>=) less than( ( SELECT AVG(amount) We will use the table payments in the sample database for the demonstration. Using a MySQL subquery in the WHERE clause When executing the query, MySQL evaluates the subquery first and uses the result of the subquery for the outer query. The outer query selects the last name and first name of employees who work in the offices whose office codes are in the result set returned by the subquery.The subquery returns all office codes of the offices located in the USA.SELECTĬountry = 'USA') Code language: SQL (Structured Query Language) ( sql ) A subquery can be used anywhere that expression is used and must be closed in parentheses.įor example, the following query uses a subquery to return the employees who work in the offices located in the USA. Also, a subquery can be nested within another subquery.Ī MySQL subquery is called an inner query while the query that contains the subquery is called an outer query. Introduction to the MySQL SubqueryĪ MySQL subquery is a query nested within another query such as SELECT, INSERT, UPDATEor DELETE. Summary: in this tutorial, we will show you how to use the MySQL subquery to write complex queries and explain the correlated subquery concept.
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