CREATE TABLE class0328( id INT, cname VARCHAR(20), sex VARCHAR(2), age INT, birthday DATE, score DOUBLE, html DOUBLE, js DOUBLE ); DESC class0328; DROP TABLE class0328 INSERT INTO class0328 VALUES(1,'董斌','男',25,'1993-09-13',80,20,60); INSERT INTO class0328 VALUES(2,'张锐','男',25,'1993-09-25',81,31,50); INSERT INTO class0328 VALUES(3,'王荣臣','男',23,'1996-07-07',30,50,30); INSERT INTO class0328 VALUES(4,'韩凯','男',26,'1991-05-20',25,20,70); INSERT INTO class0328 VALUES(5,'张禄','男',26,'1991-03-02',60,60,30); INSERT INTO class0328 VALUES(6,'刘继勋','男',24,'1994-11-27',0.5,90,60); INSERT INTO class0328 VALUES(7,'张维','男',29,'1989-02-24',100,20,79); INSERT INTO class0328 VALUES(8,'牛攀','男',29,'1989-12-24',100,50,70); INSERT INTO class0328 VALUES(9,'王祖贤','女',19,'20000101',100,50,20); INSERT INTO class0328 VALUES(10,'刘亦菲','',21,'20050201',99,60,30); INSERT INTO class0328(id,cname,sex,age) VALUES(11,'迪丽热巴','女',25); /*查询所有列*/ SELECT * FROM class0328; /*查询指定列*/ SELECT cname,sex FROM class0328; /*查询时添加常量列*/ SELECT cname AS '姓名',sex AS '性别' FROM class0328; /*查询时合并列*/ SELECT cname,(html+js) AS '总成绩' FROM class0328; /*查询时去除重复记录*/ SELECT DISTINCT sex FROM class0328; /*条件查询*/ SELECT * FROM class0328 WHERE id=1 AND sex='男'; SELECT * FROM class0328 WHERE sex='女' OR age=25; SELECT cname FROM class0328 WHERE html>60; SELECT * FROM class0328 WHERE html<>60; SELECT * FROM class0328 WHERE html>=20 AND html<=60; SELECT * FROM class0328 WHERE html BETWEEN 20 AND 60; /*判空条件*/ SELECT * FROM class0328 WHERE html IS NULL; SELECT * FROM class0328 WHERE html IS NOT NULL; SELECT * FROM class0328 WHERE sex=''; SELECT * FROM class0328 WHERE sex<>''; SELECT * FROM class0328 WHERE html IS NULL OR sex=''; SELECT * FROM class0328 WHERE html IS NOT NULL AND sex<>''; /*模糊条件*/ SELECT * FROM class0328 WHERE cname LIKE '王%'; SELECT * FROM class0328 WHERE cname LIKE '王__'; /*聚合查询*/ SELECT SUM(html) FROM class0328; SELECT SUM(html) AS 'HTML总成绩' FROM class0328; SELECT SUM(html + js) FROM class0328; SELECT AVG(html) AS 'HTML平均' FROM class0328; SELECT MAX(js) AS '最大值' FROM class0328; SELECT MIN(js) AS '最小值' FROM class0328; SELECT cname,MIN(js) AS '最小值' FROM class0328; SELECT COUNT(*) FROM class0328; SELECT COUNT(sex) FROM class0328; SELECT COUNT(html) FROM class0328; /*分页查询*/ SELECT * FROM class0328 LIMIT 0,2; SELECT * FROM class0328 LIMIT 2,2; SELECT * FROM class0328 LIMIT 4,2; SELECT * FROM class0328 LIMIT 6,2; SELECT * FROM class0328 LIMIT 8,2; SELECT * FROM class0328 LIMIT 10,2; /*查询排序*/ SELECT * FROM class0328 ORDER BY html ASC; SELECT * FROM class0328 ORDER BY html DESC; SELECT * FROM class0328 ORDER BY html ASC,js DESC; /*分组查询*/ SELECT sex,COUNT(sex) FROM class0328 GROUP BY sex; SELECT html,COUNT(*) FROM class0328 GROUP BY html HAVING html>60; SELECT sex,COUNT(*) FROM class0328 GROUP BY sex HAVING COUNT(*)>2;