A.SELECT * FROM 仓库表 WHERE IN; (SELECT 仓库号 FROM 职工表) B.SELECT * FROM 仓库表 WHERE NOT IN; (SELECT 仓库号 FROM 职工表) C.SELECT * FROM 仓库表 WHERE 仓库号 EXISTS; (SELECT * FROM 职工表 WHERE 仓库号=仓库表.仓库号) D.SELECT * FROM 仓库表 WHERE EXISTS; (SELECT * FROM 职工表 WHERE 仓库号=仓库表.仓库号)