SQL UNION Operator

The SQL UNION Operator

The UNION operator is used to combine the result-set of two or more SELECT statements.

• Every SELECT statement within UNION must have the same number of columns
• The columns must also have similar data types
• The columns in every SELECT statement must also be in the same order

UNION Syntax

SELECT column_name(s) FROM table1
UNION
SELECT column_name(s) FROM table2;

Demo Database

In this tutorial, we will use the well-known Northwind sample database.

Selection from the "Customers" table:

Selection from the "Suppliers" table:

SELECT City FROM Customers
UNION
SELECT City FROM Suppliers
ORDER BY City;