DROP TABLE IF EXISTS t1;

SET @a='test';

SELECT @a;

Field   1:  `@a`

Catalog:    `def`

Database:   ``

Table:      ``

Org_table:  ``

Type:       MEDIUM_BLOB

Collation:  utf8_general_ci (33)

Length:     50331645

Max_length: 4

Decimals:   31

Flags:      

+------+

| @a   |

+------+

| test |

+------+

DROP TABLE IF EXISTS t1;

CREATE TABLE t1 AS SELECT @a;

SHOW CREATE TABLE t1; 

+-------+-----------------------------------------------------------------------------------------------+

| Table | Create Table                                                                                  |

+-------+-----------------------------------------------------------------------------------------------+

| t1    | CREATE TABLE `t1` (

  `@a` longtext CHARACTER SET utf8

) ENGINE=InnoDB DEFAULT CHARSET=latin1 |

+-------+-----------------------------------------------------------------------------------------------+

CREATE OR REPLACE TABLE t1 AS SELECT @a:=1;

DESCRIBE t1;

+-------+--------+------+-----+---------+-------+

| Field | Type   | Null | Key | Default | Extra |

+-------+--------+------+-----+---------+-------+

| @a:=1 | int(1) | NO   |     | 0       |       |

+-------+--------+------+-----+---------+-------+

SELECT @a:=1;

Field   1:  `@a:=1`

Type:       LONGLONG

Length:     3

Max_length: 1