mysql查询必练50题

摘要：--1、查询“01”课程比“02”课程成绩高的所有学生的学号；SELECTa.sidFROM(SELECTsid,scoreFROMscWHEREcid=01)a,(SELECTsid,scoreFROMscWHEREcid=02)bWHEREa.score>b.scoreANDa.sid=b.sid;SELECTa.sidFROMstudentaLEFTJOINSCbONb.cid=01ANDa.sid=b.sidLEFTJOINSCcONc.cid=02ANDa.sid=c.sidWHEREb.score>