Important

The SingleStore 9.1 release candidate (RC) is available now. It will be promoted to general availability (GA) soon and at that time it will be renamed to SingleStore 10.

In the interim, SingleStore 9.1 RC can be used to preview, evaluate, and provide feedback on the new and upcoming features in SingleStore 10, while SingleStore 9.0 is recommended for production workloads.

UNION

Syntax

SELECT ...
UNION [ALL | DISTINCT] SELECT ...
[UNION [ALL | DISTINCT] SELECT ...]

Remarks

The first and all subsequent SELECT statements must select the same number of columns.
UNION statements are converted into nested sub-select queries by the query processor.
The maximum depth of nested sub-select queries is 40. Beyond this the UNION statements are converted to TABLE, allowing you to write up to 337 statements (0-336).

Examples

SQL

SELECT * FROM table_a UNION ALL SELECT * FROM table_b;
SELECT * FROM table_a UNION SELECT * FROM table_b;

SQL

SELECT * FROM id_t UNION ALL SELECT * FROM id_t2;

 +------+----------------------------------------------------------------------------+
 | a    | b                                                                          |
 +------+----------------------------------------------------------------------------+
 |    1 | 0xE82C75FA86974BE7903270F4353D865C                                         |
 |    1 | 0x31343865306665352D666666322D346363362D383634622D313838303637313135653236 |
 +------+----------------------------------------------------------------------------+