1 MySQL中如何实现以下SQL查询 (SELECT S.Name FROM STUDENT S, TRANSCRIPT T WHERE S.StudId = T.StudId AND T.CrsCode = 'CS305') INTERSECT (SELECT S.Name FROM STUDENT S, TRANSCRIPT T WHERE S.StudId = T.StudId AND T.CrsCode = 'CS315') 请各位不吝赐教，小弟先谢过~ 解： 取交集 select a.* from ( SELECT S.Name FROM STUDENT S, TRANSCRIPT T WHERE S.StudId = T.StudId AND T.CrsCode = 'CS305' ) as a cross join ( SELECT S.Name FROM STUDENT S, TRANSCRIPT T WHERE S.StudId = T.StudId AND T.CrsCode = 'CS315' ) as b on a.Name = b.Name;
2. SELECT * FROM ( SELECT DISTINCT col1 FROM t1 WHERE... UNION ALL SELECT DISTINCT col1 FROM t1 WHERE... ) AS tbl GROUP BY tbl.col1 HAVING COUNT(*) = 2
3. 交集： SELECT * FROM table1 AS a JOIN table2 AS b ON a.name =b.name 举例： 表a: FieldA 001 002 003 表b: FieldA 001 002 003 004 请教如何才能得出以下结果集，即表A, B行交集 FieldA 001 002 003 答案：select a.FieldA from a inner join b on a.FieldA=b.FieldA 差集： NOT IN 表示差集 SELECT * FROM table1 WHERE name NOT IN (SELECT name FROM table2)
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