COLUMN_ADD

MariaDB starting with 5.3

The Dynamic columns feature was introduced in MariaDB 5.3.

Syntax

COLUMN_ADD(dyncol_blob, column_nr, value [as type], [column_nr, value [as type]]...);
COLUMN_ADD(dyncol_blob, column_name, value [as type], [column_name, value [as type]]...);

Description

Adds or updates dynamic columns.

  • dyncol_blob must be either a valid dynamic columns blob (for example, COLUMN_CREATE returns such blob), or an empty string.
  • column_name specifies the name of the column to be added. If dyncol_blob already has a column with this name, it will be overwritten.
  • value specifies the new value for the column. Passing a NULL value will cause the column to be deleted.
  • as type is optional. See #datatypes section for a discussion about types.

The return value is a dynamic column blob after the modifications.

Examples

-- MariaDB 5.3+:
UPDATE tbl SET dyncol_blob=COLUMN_ADD(dyncol_blob, 1 /*column id*/, "value") WHERE id=1;
-- MariaDB 10.0.1+:
UPDATE t1 SET dyncol_blob=COLUMN_ADD(dyncol_blob, "column_name", "value") WHERE id=1;

Note: COLUMN_ADD() is a regular function (just like CONCAT()), hence, in order to update the value in the table you have to use the UPDATE ... SET dynamic_col=COLUMN_ADD(dynamic_col, ....) pattern.

Comments

Comments loading...
Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.