目录

创建表

根据上面表格进行的查询操作

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创建表

        学生表：stu

#创建学生表
CREATE TABLE stu(
	sid CHAR(6),
	sname VARCHAR(50),
	age INT,
	gender VARCHAR(50)
);

#向学生表中插入下面数据
INSERT INTO stu VALUES('S_1001','liuYi',35,'male');
INSERT INTO stu VALUES('S_1002','chenEr',15,'female');
INSERT INTO stu VALUES('S_1003','ZhangSan',95,'male');
INSERT INTO stu VALUES('S_1004','liSi',35,'female');
INSERT INTO stu VALUES('S_1005','wangWu',55,'male');
INSERT INTO stu VALUES('S_1006','zhangLiu',75,'female');
INSERT INTO stu VALUES('S_1007','sunQi',25,'male');
INSERT INTO stu VALUES('S_1008','zhouBa',45,'female');
INSERT INTO stu VALUES('S_1009','wuJiu',85,'male');
INSERT INTO stu VALUES('S_1010','zhengShi',5,'female');
INSERT INTO stu VALUES('S_1011','xxx',NULL,NULL);

雇员表：

#创建雇员表
CREATE TABLE emp(
	empno INT,
	ename VARCHAR(50),
	job VARCHAR(50),
	mgr INT,
	hiredate DATE,
	sal DECIMAL(7,2),
	comm DECIMAL(7,2),
	deptno INT

);

#向雇员表插入数据
INSERT INTO emp VALUES(7369,'SMITH','ClERK',7902,'1980-12-17',800,NULL,20)
INSERT INTO emp VALUES(7499,'ALLEN','SALESMAN',7698,'1981-02-20',1600,300,30);
INSERT INTO emp VALUES(7521,'WARD','SALESMAN',7698,'1981-02-22',1250,500,30);
INSERT INTO emp VALUES(7566,'JONES','MANAGER',7839,'1981-04-02',2975,NULL,20);
INSERT INTO emp VALUES(7654,'MARTIN','SALESMAN',7698,'1981-09-28',1250,1400,30);
INSERT INTO emp VALUES(7698,'BLAKE','MANAGER',7839,'1981-05-01',2850,NULL,30);
INSERT INTO emp VALUES(7782,'CLARK','MANAGER',7839,'1981-06-09',2450,NULL,10);
INSERT INTO emp VALUES(7788,'SCOTT','ANALYST',7566,'1987-04-19',3000,NULL,20);
INSERT INTO emp VALUES(7839,'KING','PRESIDENT',NULL,'1981-11-17',5000,NULL,10);
INSERT INTO emp VALUES(7844,'TURNER','SALESMAN',7698,'1981-09-08',1500,0,30);
INSERT INTO emp VALUES(7876,'ADAMS','CLERK',7788,'1987-05-23',1100,NULL,20);
INSERT INTO emp VALUES(7900,'JAMES','CLERK',7698,'1981-12-03',950,NULL,30);
INSERT INTO emp VALUES(7902,'FORD','ANALYST',7566,'1981-12-03',3000,NULL,20);
INSERT INTO emp VALUES(7934,'MILLER','CLERK',7782,'1982-01-23',1300,NULL,10);

部门表

CREATE TABLE dept(
	ddeptno INT,
	dname VARCHAR(14),
	loc VARCHAR(13)
)

#向部门表中插入数据
INSERT INTO dept VALUES(10, 'ACCOUNTING', 'NEW YORK');
INSERT INTO dept VALUES(20, 'RESEARCH', 'DALLAS');
INSERT INTO dept VALUES(30, 'SALES', 'CHICAGO');
INSERT INTO dept VALUES(40, 'OPERATIONS', 'BOSTON');

根据上面表格进行的查询操作

##练习题目

#对学生表操作

#1、查询性别为女，并且年龄50的记录
SELECT * FROM stu WHERE gender='female' AND age<50;

#2、查询学号为S_1001，或者姓名为liSi的记录
SELECT * FROM stu WHERE sid='S_1001' OR sname='liSi';


#3、查询学号为S_1001，S_1002，S_1003的记录
SELECT * FROM stu WHERE sid IN('S_1001','S_1002','S_1003');

#4、查询学号不是S_1001，S_1002，S_1003的记录
SELECT * FROM stu WHERE sid NOT IN ('S_1001','S_1002','S_1003');


#5、查询年龄为null的记录
SELECT * FROM stu WHERE age IS NULL;

#6、查询年龄在20到40之间的学生记录
SELECT *FROM stu WHERE age>=20 AND age<=40;#或者
SELECT * FROM stu WHERE age BETWEEN 20 AND 40;

#7、查询性别非男的学生记录
SELECT * FROM stu WHERE gender!='male';#或者
SELECT * FROM stu WHERE gender <>'male';#或者
SELECT * FROM stu WHERE NOT gender='male';

#8、查询姓名不为null的学生记录
SELECT * FROM stu WHERE sname IS NOT NULL;#或者
SELECT * FROM stu WHERE NOT sname IS NULL;

#9、查询姓名由5个字母构成的学生记录
SELECT * FROM stu WHERE sname LIKE '_____'; #一个字母用一个下划线代表

#10、查询姓名由5个字母构成，并且第5个字母为“i”的学生记录
SELECT * FROM stu WHERE sname LIKE '____i';

#11、查询姓名以“z”开头的学生记录
SELECT * FROM stu WHERE sname LIKE 'z%'; #其中%匹配0-n个任意字母

#12、查询姓名中第2个字母为“i”的学生记录
SELECT * FROM stu WHERE sname LIKE '_i%';

#13、查询姓名中包含“a”字母的学生记录
SELECT * FROM stu WHERE sname LIKE '%a%';

#14、查询所有学生记录，按年龄升序排序
SELECT * FROM stu ORDER BY age ASC;
SELECT * FROM stu ORDER BY age; #默认升序排序

#15、查询所有学生记录，按年龄降序排序
SELECT *FROM stu ORDER BY age DESC;



##雇员表格操作

#16、查询所有雇员，按月薪降序排序，如果月薪相同时，按编号升序排序
SELECT * FROM emp ORDER BY sal DESC,empno ASC;

#17、查询emp表中月薪大于2500的人数：
SELECT COUNT(*) FROM emp WHERE sal>2500;

#18、统计月薪与佣金之和大于2500元的人数：
SELECT COUNT(*) AS cnt FROM emp WHERE sal+IFNULL(comm,0)>2500;

#19、查询有佣金的人数，以及有领导的人数：
SELECT COUNT(comm),COUNT(mgr) FROM emp;

#20、查询所有雇员月薪和，以及所有雇员佣金和：
SELECT SUM(sal),SUM(comm) FROM emp;

#21、查询所有雇员月薪+佣金和：
SELECT SUM(sal+IFNULL(comm,0)) FROM emp;

#22、统计所有员工平均工资：
SELECT SUM(sal)/COUNT(sal) FROM emp;#或者
SELECT AVG(sal)FROM emp;

#23、查询每个部门的部门编号和每个部门的工资和：
SELECT deptno ,SUM(sal) FROM emp GROUP BY deptno;

#24、查询每个部门的部门编号以及每个部门的人数：
SELECT deptno ,COUNT(*) FROM emp GROUP BY deptno;

#25、查询每个部门的部门编号以及每个部门工资大于1500的人数：
SELECT deptno,COUNT(*) FROM emp WHERE sal>1500 GROUP BY deptno;

#26、查询工资总和大于9000的部门编号以及工资和：
SELECT deptno,SUM(sal) FROM emp GROUP BY deptno HAVING SUM(sal)>9000;

#27、查询5行记录，起始行从0开始
SELECT * FROM emp LIMIT 0,5;

#28、查询10行记录，起始行从3开始
SELECT * FROM emp LIMIT 3,10;