MySQL 5. Subqueries and Links

SQL: Structured Query Language

Sub-query:

• Subqueries are nested inside a query and must always appear inside parentheses
• A subquery can contain multiple keywords or conditions, such as distinct, GROUP by, ORDER by, LIMIT, function, and so on.
• The outer query of a subquery can be a generic term for all of the SQL commands that we know.

In the following example, select * FROM table1 is called outer query/out Statement

SELECT col2 from Table2 called subquery

1 SELECT *  from WHERE = (SELECT from table2);

A subquery can return a scalar, a row, a column, or a subquery

MySQL 5. Subqueries and Links