MySQL高級查詢習題

MySQL高級查詢習題

提示：
emp員工表(empno員工號/ename員工姓名/job工作/mgr上級編號/hiredate受僱日期/sal薪金/comm佣金/deptno所屬部門編號)
dept部門表(deptno部門編號/dname部門名稱/loc地點)
工資 ＝ 薪金 ＋ 佣金
首先先知道主外鍵的關係，從提示中不難看出 dept 部門表是主鍵，emp 員工表是外鍵

在Emp 表中完成如下練習：

– 創建部門表

CREATE TABLE dept(
teptno VARCHAR(20) PRIMARY KEY,
dname VARCHAR(20),
loc VARCHAR(20));

– 創建員工表

CREATE TABLE emp(empno VARCHAR(20) PRIMARY KEY,
ename VARCHAR(20),
job VARCHAR(20),
mar VARCHAR(20),
hiredate DATE,
sal DOUBLE,
comm DOUBLE,
deptno VARCHAR(20) REFERENCES dept(deptno));

– 給部門表添加數據

INSERT INTO dept(teptno,dname,loc) VALUES("1","研發部","六樓");
INSERT INTO dept(teptno,dname,loc) VALUES("2","測試部","五樓");
INSERT INTO dept(teptno,dname,loc) VALUES("3","銷售部","四樓");
INSERT INTO dept(teptno,dname,loc) VALUES("4","推广部","三樓");
INSERT INTO dept(teptno,dname,loc) VALUES("5","生產部","二樓");
INSERT INTO dept(teptno,dname,loc) VALUES("6","諮詢部","一樓");

– 給員工表添加數據

INSERT INTO emp VALUES("001","小團團","java開發工程師","111","2020-01-15",10000,4000,"1");
INSERT INTO emp VALUES("002","韓冰","妲己","111","2019-02-14",20000,2000,"2");
INSERT INTO emp VALUES("003","呆妹","java諮詢師","111","2019-03-14",10000,1000,"3");
INSERT INTO emp VALUES("004","Uzi","烏老師","111","2017-05-14",50000,5000,"4");
INSERT INTO emp VALUES("005","letme","理論大師","111","2017-04-14",20000,8000,"5");
INSERT INTO emp VALUES("006","七七餓了","金牌講師","111","2019-08-14",10000,2000,"6");
INSERT INTO emp VALUES("007","小橙子","金牌講師","111","2020-07-14",20000,5000,"6");
INSERT INTO emp VALUES("008","小橘子","java開發工程師","111","2020-09-25",50000,5000,"1");
INSERT INTO emp VALUES("010","小兔子","老師","111","2020-10-01",30000,000,"6");
INSERT INTO emp VALUES("011","達摩","峽谷藝術家","111","2017-09-14",10000,2000,"3");

1、在emp表中查詢出所有的記錄。

-- 1、在emp表中查詢出所有的記錄。
SELECT * FROM emp;

2、在emp表中查詢出薪水大於1500的記錄，並且按照薪水的降序排列。

-- 2、在emp表中查詢出薪水大於1500的記錄，並且按照薪水的降序排列。
SELECT * FROM emp ORDER BY sal+comm DESC;

3、在emp表中查詢出comm字段爲空值的記錄。

-- 3、在emp表中查詢出comm字段爲空值的記錄。
-- 先添加一個comm爲空的數據
INSERT INTO emp (empno,ename,job,mar,hiredate,sal,deptno)VALUES("011","豬八戒","峽谷藝術家","111","2015-12.12","9000","2");
SELECT * FROM emp WHERE comm IS NULL;

4、查詢出emp表中含有幾個部門的記錄。（用DISTINCT去除重複記錄）

-- 4、查詢出emp表中含有幾個部門的記錄。（用DISTINCT去除重複記錄）
SELECT COUNT(DISTINCT deptno) FROM emp;

5、在emp表中查詢出部門編號爲5或6的記錄。（要求使用IN關鍵字）

-- 5、在emp表中查詢出部門編號爲5或6的記錄（要求使用IN關鍵字）
SELECT* FROM emp WHERE deptno IN(5,6);

6、在emp表中查詢出姓名的第二個字母爲A的記錄。

-- 6、在emp表中查詢出姓名的第二個字母爲A的記錄。
-- 先添加一條第二個字母爲A的數據
INSERT INTO emp VALUES("012","AAA","峽谷藝術家","111","2017-09-18",10000,6000,"3");
SELECT * FROM emp WHERE ename LIKE "_A%";

7、查詢出emp表中總共有多少條記錄。

-- 7、查詢出emp表中總共有多少條記錄。
SELECT COUNT(*) FROM emp;

8、查詢emp表中出每個部門的部門代碼、薪水之和、平均薪水。

-- 8、查詢emp表中出每個部門的部門代碼、薪水之和、平均薪水
SELECT AVG(sal+IFNULL(comm,0))AS '平均薪水',SUM(sal+IFNULL(comm,0))AS '薪水之和',deptno AS '部門編號' FROM emp GROUP BY deptno;

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