MySQL UNION usage

This article shows you how to use UNION in MySQL to combine more query output into a single result set.

Tutorial info:

Name:	MySQL UNION usage
Total steps:	1
Category:	MySQL
Date:	2010-11-10
Level:	Beginner
Product:	See complete product
Viewed:	5648

Bookmark MySQL UNION usage

Step 1 - MySQL Union usage

MySQL UNION usage

With UNION you can combine two or more SQL queries into a single result set.

The syntax is the following:

Code:

```
SELECT field1, field2 ...
```
```
UNION [ALL | DISTINCT]
```
```
SELECT field1, field2 ...
```
```
...
```

Database F1

There are some important rules you have to note:

Every SELECT statement must have the same number of fields.
The datatype of the appropriate fields must be the same - or at least convertible - in the various SELECT statements

Let’s see an example if you want to get all brands from your tables like car, computer and clothing. In this case you have 3 query:

Code:

```
SELECT brand FROM car;
```
```
SELECT brand FROM computer;
```
```
SELECT brand FROM clothing;
```
```
 
```

Database F1

To join the 3 result into one:

Code:

```
SELECT brand FROM car
```
```
UNION 
```
```
SELECT brand FROM computer
```
```
UNION 
```
```
SELECT brand FROM clothing;
```

Database F1

By default the UNION works as if DISTINCT keyword would be used so no duplication will be present in the result list. If you want to get every record without filtering out duplicated items use the UNION ALL format as here:

Code:

```
SELECT brand FROM car
```
```
UNION ALL
```
```
SELECT brand FROM computer
```
```
UNION ALL
```
```
SELECT brand FROM clothing;
```

Database F1

Tags: mysql union, sql union, union, combine result sets, combine

MySQL UNION usage - Table of contents
Step 1 - MySQL Union usage

Database F1

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MySQL UNION usage

Tutorial info:

Bookmark MySQL UNION usage

Step 1 - MySQL Union usage