MySQL: COLUMN_DEFAULT is always NULL for non null default values

Question

CREATE TABLE `test` (
`id` INT(10) UNSIGNED NOT NULL,
`c1` VARCHAR(60) NULL DEFAULT NULL,
`c2` VARCHAR(60) NOT NULL,
PRIMARY KEY (`id`)
 )

In the information_schema.columns.COLUMN_DEFAULT contains NULL for both c1,c2 columns but c2 doesn't have default value.

How to get the real COLUMN_DEFAULT value?

Answer 1

In information_schema.columns , if COLUMN_DEFAULT is NULL and IS_NULLABLE is NO then it doesn't have a default.

But basically you can see it as: the default, if not specified, is always NULL . So, c2 isn't allowed to be NULL , but it will default to NULL , thus will always need to be specified on insert statements.

Note: a field specified as NOT NULL doesn't need to be able to represent NULL , thus it can theoretically take up (slightly) less space.