Warning

SingleStore 9.0 gives you the opportunity to preview, evaluate, and provide feedback on new and upcoming features prior to their general availability. In the interim, SingleStore 8.9 is recommended for production workloads, which can later be upgraded to SingleStore 9.0.

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 |
 +------+----------------------------------------------------------------------------+