The SQL UNION query is used to merge two or more SQL SELECT query results. Each query statement should have same column structure: same number of columns, same or compatible data types and in same order.
Note: The result of SQL UNION query is distinct.
SQL UNION Query Syntax
SELECT Column(s) FROM Table1 UNION SELECT Column(s) FROM Table2
SQL UNION Query Example
Table: FinanceEmployees
EmployeeId | FirstName | LastName |
---|---|---|
203 | Kilooa | Joooo |
204 | Hioiaaa | Hifa |
205 | Yuiofa | Iioooa |
206 | Miofa | Poqqq |
EmployeeId | FirstName | LastName |
---|---|---|
206 | Miofa | Poqqq |
207 | Qifaww | Siafoa |
208 | Ziooo | Rrroo |
209 | UUifad | Bbiiw |
Select all the different employees in FinanceEmployees and DevelopmentEmployees:
SELECT EmployeeId, FirstName, LastName FROM FinanceEmployees UNION SELECT EmployeeId, FirstName, LastName FROM DevelopmentEmployees
The result will look like:
EmployeeId | FirstName | LastName |
---|---|---|
203 | Kilooa | Joooo |
204 | Hioiaaa | Hifa |
205 | Yuiofa | Iioooa |
206 | Miofa | Poqqq |
207 | Qifaww | Siafoa |
208 | Ziooo | Rrroo |
209 | UUifad | Bbiiw |