SQL – Union
Table Of Contents:
- What Is SQL Union?
- Syntax Of SQL Union.
- Examples Of SQL Union.
(1) What Is SQL Union ?
The
UNIONthe operator is used to combine the result set of two or moreSELECTstatements.Every
SELECTstatement withinUNIONmust have the same number of columns.The columns must also have similar data types
The columns in every
SELECTstatement must also be in the same order
(2) Syntax Of SQL Union ?
Syntax: UNION Syntax
SELECT column_name(s) FROM table1
UNION
SELECT column_name(s) FROM table2;Syntax: UNION ALL Syntax
SELECT column_name(s) FROM table1
UNION ALL
SELECT column_name(s) FROM table2;Note:
- The
UNIONthe operator selects only distinct values by default. To allow duplicate values, useUNION ALL:
(3) Examples Of SQL Union ?
Customer Table:
Suppliers Table:
Example-1: SQL UNION Example
SELECT City FROM Customers
UNION
SELECT City FROM Suppliers
ORDER BY City;
Example-2: SQL UNION ALL Example
SELECT City FROM Customers
UNION ALL
SELECT City FROM Suppliers
ORDER BY City;
Example-3: SQL UNION With WHERE
SELECT City, Country FROM Customers
WHERE Country='Germany'
UNION
SELECT City, Country FROM Suppliers
WHERE Country='Germany'
ORDER BY City;
Example-4: SQL UNION ALL With WHERE
SELECT City, Country FROM Customers
WHERE Country='Germany'
UNION ALL
SELECT City, Country FROM Suppliers
WHERE Country='Germany'
ORDER BY City;