adding column to all tables in a mysql database (unknown table names)

Question

I need to add a primary key to a set of tables in a given database. I do not know how many tables there will be or what their specific names are. They will all be of the for dat

Answer 1

You can do the following to change the columns. This uses a cursor to iterate over the table names and does not use text files or anything. You have to create this as a stored proc as cursors cannot be used outside.

DELIMITER $$

USE `db_name`$$

DROP PROCEDURE IF EXISTS `alter_test_1`$$

CREATE DEFINER=`db_name`@`10.%` PROCEDURE `alter_test_1`()
BEGIN

DECLARE v_finished INTEGER DEFAULT 0;
DECLARE v_table VARCHAR(100) DEFAULT "";
DECLARE stmt VARCHAR(500) DEFAULT "";

DECLARE column_cursor CURSOR FOR
SELECT * FROM `information_schema`.`tables` WHERE table_schema = 'db_name' AND table_name LIKE 'mytables_%';

DECLARE CONTINUE HANDLER
FOR NOT FOUND SET v_finished = 1;

OPEN column_cursor;

alter_tables: LOOP

FETCH column_cursor INTO v_table;
IF v_finished = 1 THEN
LEAVE alter_tables;
END IF;

SET @prepstmt = CONCAT('ALTER TABLE adtracker','.',v_table,'  ADD COLUMN id INT AUTO_INCREMENT NOT NULL;');

PREPARE stmt FROM @prepstmt;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

END LOOP alter_tables;

CLOSE column_cursor;

END$$

DELIMITER ;