5AbSWMSp

1IF NOT EXISTS( SELECT NULL
2        FROM INFORMATION_SCHEMA.COLUMNS
3       WHERE table_name = 'tablename'
4         AND table_schema = 'db_name'
5         AND column_name = 'columnname')  THEN
6
7  ALTER TABLE `TableName` ADD `ColumnName` int(1) NOT NULL default '0';
8
9END IF;
10	
11DELIMITER $$
12CREATE PROCEDURE Alter_Table_With_Check()
13BEGIN
14    DECLARE _count INT;
15    SET _count = (  SELECT COUNT(*) 
16                    FROM INFORMATION_SCHEMA.COLUMNS
17                    WHERE   TABLE_NAME = 'tableName' AND 
18                            COLUMN_NAME = 'columnToAdd');
19    IF _count = 0 THEN
20        ALTER TABLE tableName
21            ADD COLUMN columnToAdd varchar(512) DEFAULT NULL;
22    END IF;
23END $$
24DELIMITER ;