--1SELECT stuID,stuName, major FROM STUENTWHERE STUID IN (SELECT STUID FROM borrow)--1_1SELECT AstuID,AstuName, Aajor FROM STUENT A,borrow BWHERE ASTUID=BSTUID--2borrow:字段borrowID(结束编号),stuID(学生编号),BID(图书编号), T_time (结束日期),B_time(还书日期)SELECT AstuName, COUNT(BID) AS 图书数量 FROM STUENT A,borrow BWHERE ASTUID=BSTUID AND GETDATE()>=BB_TIME)GROUP BY AstuName--3SELECT AstuName, BT_TIME,(case b_time is null when then DAY(BB_TIME-T_TIME)else '尚未归还'end) AS 看书天数 FROM STUENT A,borrow B,BOOK CWHERE ASTUID=BSTUID AND BBID=CBIDAND CTITLE='《天龙八部》'