Question

I want check, exists or not in mytable column “auto”, and if not exists, add his. a make this so:

  mysql-> SHOW COLUMNS FROM mytable 

after, with PHP I check, in result exists or not “auto” and if no, I make:

  mysql-> ALTER TABLE mytable  ADD auto  VARCHAR (30) NOT NULL COLLATE utf8_general_ci 

Question: please tell, how to make this in one query ?

Answer 1

You can define following query in your stored procedure and call the stored procedure to add the column if not exist.

IF NOT EXISTS(
    SELECT * FROM information_schema.COLUMNS
    WHERE COLUMN_NAME='auto' AND TABLE_NAME='my_table' AND TABLE_SCHEMA='the_schema'
    )
    THEN
        ALTER TABLE `the_schema`.`my_table`
        ADD COLUMN `auto` VARCHAR (30) NOT NULL COLLATE utf8_general_ci ;

END IF;