MySQL UNION Operator (original) (raw)
Last Updated : 26 Mar, 2026
The UNION operator in MySQL combines the results of multiple SELECT statements into a single result set. It ensures consistent structure by requiring the same number of columns with compatible data types.
- Removes duplicate records from the final combined result.
- Uses column names from the first SELECT statement for the output.
**Syntax:
SELECT column1, column2, ... FROM table1 WHERE condition UNION SELECT column1, column2, ... FROM table2 WHERE condition;
- **column1, column2, ...: Columns selected from each SELECT statement must be the same in number and compatible in data type.
- **table1, table2, ...: The tables or views from which data is selected.
- **condition: Optional conditions to filter rows in each SELECT statement.
**Note: UNION removes duplicate records by default.
Working with the MySQL UNION Operator
Let’s explore how the MySQL UNION operator works using examples. These examples demonstrate how to combine results from multiple tables. First, let’s create two tables on which the UNION operator will be applied:
students Table
teachers Table
Example 1: Combining Names from Students and Teachers Table
This example shows how to merge names from two tables into a single result. It also adds a label to identify the source of each record.
**Query:
SELECT name, 'Student' AS type FROM students UNION SELECT name, 'Teacher' AS type FROM teachers;
**Output:
- Combines names from both tables into one result set.
- Adds a type column to distinguish between students and teachers.
Example 2: Combining Names with Conditions
This example demonstrates combining filtered data from both tables. It helps retrieve only relevant records based on conditions.
**Query:
SELECT name, 'Student' AS type FROM students WHERE age > 15 UNION SELECT name, 'Teacher' AS type FROM teachers WHERE years_of_experience > 8;
**Output:
- Filters students and teachers based on specified conditions.
- Combines only the qualifying records into a single result.