mysql实现多表关联

mysql实现多表关联

SELECT `back_role_menu`.id, `back_role`.role_name,`back_menu`.menu_name FROM `back_role_menu`
LEFT JOIN `back_role` ON `back_role_menu`.role_id = `back_role`.id
LEFT JOIN `back_menu` ON `back_role_menu`.menu_id = `back_menu`.id

mysql关联单张表

SELECT `back_role_menu`.id, `back_role`.role_name,`back_menu`.menu_name FROM `back_role_menu`
LEFT JOIN `back_role` ON `back_role_menu`.role_id = `back_role`.id