mysql中工资排名前十的所有员工的姓名,并且显示最高工资的员工与各个员工工资的差

declare @max int

select @max =max(工资) from 表

select * from 表 where 工资= @max

select top 10 员工,@max-工资 as 工资差额 from 表 order by 工资 desc

希望采纳

-- 查询分类名称为手机数码的所有商品

1.查询分类名为手机数码的ID

SELECT cid FROM category WHERE cname='手机数码'

2.得出ID为1的结果

SELECT * FROM product WHERE cno = (SELECT cid FROM category WHERE cname='手机数码')

子查询练习:

子查询练习及答案:

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

)

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)

INSERT INTO emp VALUES(7981,'MILLER','CLERK',7788,'1992-01-23',2600,500,20)

CREATE TABLE dept(

deptno INT,

dname VARCHAR(14),

loc VARCHAR(13)

)

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')

--最高工资

SELECT MAX(sal) FROM emp

--最少工资

SELECT MIN(sal) FROM emp

--最高工资的员工信息

SELECT * FROM emp WHERE sal = (SELECT MAX(sal) FROM emp)

--最低工资的员工信息

SELECT * FROM emp WHERE sal = (SELECT MIN(sal) FROM emp)

-- 单行子查询(><>= <= = <>)

-- 查询出高于10号部门的平均工资的员工信息

1.10号部门的平均工资

SELECT AVG(sal) FROM emp WHERE deptno = 10

2. 高于上面结果员工信息

SELECT * FROM emp WHERE sal >(SELECT AVG(sal) FROM emp WHERE deptno = 10)

-- 多行子查询(in not in any all)>any >all

-- 查询出比10号部门任何员工薪资高的员工信息

1. 查询出10号部门最高工资

SELECT MAX(sal) FROM emp WHERE deptno = 10

2. 得出结果

SELECT * FROM emp WHERE sal >(SELECT MAX(sal) FROM emp WHERE deptno = 10)

-- 查询出比10号部门任意一个员工薪资高的所有员工信息 : 只要比其中随便一个工资都可以

SELECT sal FROM emp WHERE deptno = 10

-- 多列子查询(实际使用较少) in

-- 和10号部门同名同工作的员工信息

1. 查询出10号部门所有人 名字和工作

SELECT ename,job FROM emp WHERE deptno=10

2. 得出结果

SELECT * FROM emp WHERE (ename,job) IN (SELECT ename,job FROM emp WHERE deptno=10) AND deptno !=10

-- Select后面接子查询

-- 获取员工的名字和部门的名字

SELECT ename,deptno FROM emp

-- from后面接子查询

-- 查询emp表中所有管理层的信息

SELECT DISTINCT mgr FROM emp

-- where 接子查询

-- 薪资高于10号部门平均工资的所有员工信息

1. 10号部门平均工资

SELECT AVG(sal) FROM emp WHERE deptno=10

2. 得出结果

SELECT * FROM emp WHERE sal >(SELECT AVG(sal) FROM emp WHERE deptno=10)

-- having后面接子查询

-- 有哪些部门的平均工资高于30号部门的平均工资

1. 统计所有的部门的平均工资

SELECT deptno, AVG(sal) FROM emp GROUP BY deptno

2. 30号部门的平均工资

SELECT AVG(sal) FROM emp WHERE deptno=30

3.得出结果:

SELECT deptno, AVG(sal) FROM emp GROUP BY deptno HAVING AVG(sal) >(SELECT AVG(sal) FROM emp WHERE deptno=30)

-- 列出达拉斯加工作的人中,比纽约平均工资高的人

原文链接： https://blog.csdn.net/mqingo/article/details/84679590

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