MySQL lpad cast ifnull regexp

SELECT
　　lpad( (CAST(IFNULL(MAX(ITEM_ID) , 0) as unsigned int) + 1), 3, '0') AS ITEM_ID
FROM 
　　REQUEST_MST_ITEM
WHERE 
　　REQUEST_TYPE = #{requestType}
　　AND LANGUAGE = #{language}
　　AND ITEM_ID regexp '[0-9]'

lpad

CAST

IFNULL

regexp