商店S(SNO,SNAME,CITY)商品P(PNO,PNAME,COLOR)销售SP(SNO,PNO,DATE,QTY)用SQL完成查询:在所有LODON商店均销售的商品名
SELECT PNAME FROM P WHERE NOT EXISTS (SELECT ? FROM S WHERE CITY=″LODON″ AND NOT EXISTS (SELECT ? FROM SP WHERE PNO=P. SNO))
商店S(SNO,SNAME,CITY)商品P(PNO,PNAME,COLOR)销售SP(SNO,PNO,DATE,QTY)用SQL完成查询:在所有LODON商店均销售的商品名
SELECT PNAME FROM P WHERE NOT EXISTS (SELECT ? FROM S WHERE CITY=″LODON″ AND NOT EXISTS (SELECT ? FROM SP WHERE PNO=P. SNO))