MySQL单表查询:
建表:
CREATE TABLE `emp` (
`empno` int(4) NOT NULL,
`ename` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
`job` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
`mgr` int(4) NULL DEFAULT NULL,
`hiredate` date NOT NULL,
`sai` int(255) NOT NULL,
`comm` int(255) NULL DEFAULT NULL,
`deptno` int(2) NOT NULL,
PRIMARY KEY (`empno`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
mysql> desc emp;
+----------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+----------+--------------+------+-----+---------+-------+
| empno | int(4) | NO | PRI | NULL | |
| ename | varchar(255) | YES | | NULL | |
| job | varchar(255) | YES | | NULL | |
| mgr | int(4) | YES | | NULL | |
| hiredate | date | NO | | NULL | |
| sai | int(255) | NO | | NULL | |
| comm | int(255) | YES | | NULL | |
| deptno | int(2) | NO | | NULL | |
+----------+--------------+------+-----+---------+-------+
插入数据:
INSERT INTO `emp` VALUES (1001, '甘宁', '文员', 1013, '2000-12-17', 8000, NULL, 20),
(1002, '黛绮丝', '销售员', 1006, '2001-02-20', 16000, 3000, 30),
(1003, '殷天正', '销售员', 1006, '2001-02-22', 12500, 5000, 30),
(1004, '刘备', '经理', 1009, '2001-04-02', 29750, NULL, 20),
(1005, '谢逊', '销售员', 1006, '2001-09-28', 12500, 14000, 30),
(1006, '关羽', '经理', 1009, '2001-05-01', 28500, NULL, 30),
(1007, '张飞', '经理', 1009, '2001-09-01', 24500, NULL, 10),
(1008, '诸葛亮', '分析师', 1004, '2007-04-19', 30000, NULL, 20),
(1009, '曾阿牛', '董事长', NULL, '2001-11-17', 50000, NULL, 10),
(1010, '韦一笑', '销售员', 1006, '2001-09-08', 15000, 0, 30),
(1011, '周泰', '文员', 1006, '2007-05-23', 11000, NULL, 20),
(1012, '程普', '文员', 1006, '2001-12-03', 9500, NULL, 30),
(1013, '庞统', '分析师', 1004, '2001-12-03', 30000, NULL, 20),
(1014, '黄盖', '文员', 1007, '2002-01-23', 13000, NULL, 10),
(1015, '张三', '保洁员', 1001, '2013-05-01', 80000, 50000, 50);
mysql> select * from emp;
+-------+-----------+-----------+------+------------+-------+-------+--------+
| empno | ename | job | mgr | hiredate | sai | comm | deptno |
+-------+-----------+-----------+------+------------+-------+-------+--------+
| 1001 | 甘宁 | 文员 | 1013 | 2000-12-17 | 8000 | NULL | 20 |
| 1002 | 黛绮丝 | 销售员 | 1006 | 2001-02-20 | 16000 | 3000 | 30 |
| 1003 | 殷天正 | 销售员 | 1006 | 2001-02-22 | 12500 | 5000 | 30 |
| 1004 | 刘备 | 经理 | 1009 | 2001-04-02 | 29750 | NULL | 20 |
| 1005 | 谢逊 | 销售员 | 1006 | 2001-09-28 | 12500 | 14000 | 30 |
| 1006 | 关羽 | 经理 | 1009 | 2001-05-01 | 28500 | NULL | 30 |
| 1007 | 张飞 | 经理 | 1009 | 2001-09-01 | 24500 | NULL | 10 |
| 1008 | 诸葛亮 | 分析师 | 1004 | 2007-04-19 | 30000 | NULL | 20 |
| 1009 | 曾阿牛 | 董事长 | NULL | 2001-11-17 | 50000 | NULL | 10 |
| 1010 | 韦一笑 | 销售员 | 1006 | 2001-09-08 | 15000 | 0 | 30 |
| 1011 | 周泰 | 文员 | 1006 | 2007-05-23 | 11000 | NULL | 20 |
| 1012 | 程普 | 文员 | 1006 | 2001-12-03 | 9500 | NULL | 30 |
| 1013 | 庞统 | 分析师 | 1004 | 2001-12-03 | 30000 | NULL | 20 |
| 1014 | 黄盖 | 文员 | 1007 | 2002-01-23 | 13000 | NULL | 10 |
| 1015 | 张三 | 保洁员 | 1001 | 2013-05-01 | 80000 | 50000 | 50 |
+-------+-----------+-----------+------+------------+-------+-------+--------+
查询数据:
查询出部门编号为30的所有员工:
mysql> select * from emp where deptno=30;
+-------+-----------+-----------+------+------------+-------+-------+--------+
| empno | ename | job | mgr | hiredate | sai | comm | deptno |
+-------+-----------+-----------+------+------------+-------+-------+--------+
| 1002 | 黛绮丝 | 销售员 | 1006 | 2001-02-20 | 16000 | 3000 | 30 |
| 1003 | 殷天正 | 销售员 | 1006 | 2001-02-22 | 12500 | 5000 | 30 |
| 1005 | 谢逊 | 销售员 | 1006 | 2001-09-28 | 12500 | 14000 | 30 |
| 1006 | 关羽 | 经理 | 1009 | 2001-05-01 | 28500 | NULL | 30 |
| 1010 | 韦一笑 | 销售员 | 1006 | 2001-09-08 | 15000 | 0 | 30 |
| 1012 | 程普 | 文员 | 1006 | 2001-12-03 | 9500 | NULL | 30 |
+-------+-----------+-----------+------+------------+-------+-------+--------+
所有销售员的姓名、编号和部门编号:
mysql> select ename,empno,deptno from emp where job='销售员';
+-----------+-------+--------+
| ename | empno | deptno |
+-----------+-------+--------+
| 黛绮丝 | 1002 | 30 |
| 殷天正 | 1003 | 30 |
| 谢逊 | 1005 | 30 |
| 韦一笑 | 1010 | 30 |
+-----------+-------+--------+
找出奖金高于工资的员工:
mysql> select * from emp where comm>sai;
+-------+--------+-----------+------+------------+-------+-------+--------+
| empno | ename | job | mgr | hiredate | sai | comm | deptno |
+-------+--------+-----------+------+------------+-------+-------+--------+
| 1005 | 谢逊 | 销售员 | 1006 | 2001-09-28 | 12500 | 14000 | 30 |
+-------+--------+-----------+------+------------+-------+-------+--------+
找出奖金高于工资60%的员工:
mysql> select * from emp where comm > sai*0.6;
+-------+--------+-----------+------+------------+-------+-------+--------+
| empno | ename | job | mgr | hiredate | sai | comm | deptno |
+-------+--------+-----------+------+------------+-------+-------+--------+
| 1005 | 谢逊 | 销售员 | 1006 | 2001-09-28 | 12500 | 14000 | 30 |
| 1015 | 张三 | 保洁员 | 1001 | 2013-05-01 | 80000 | 50000 | 50 |
+-------+--------+-----------+------+------------+-------+-------+--------+
找出部门编号为10中所有经理,和部门编号为30中所有销售员的详细资料:
mysql> select * from emp where (job='经理' and deptno=10) or (job='销售员' and deptno=30);
+-------+-----------+-----------+------+------------+-------+-------+--------+
| empno | ename | job | mgr | hiredate | sai | comm | deptno |
+-------+-----------+-----------+------+------------+-------+-------+--------+
| 1002 | 黛绮丝 | 销售员 | 1006 | 2001-02-20 | 16000 | 3000 | 30 |
| 1003 | 殷天正 | 销售员 | 1006 | 2001-02-22 | 12500 | 5000 | 30 |
| 1005 | 谢逊 | 销售员 | 1006 | 2001-09-28 | 12500 | 14000 | 30 |
| 1007 | 张飞 | 经理 | 1009 | 2001-09-01 | 24500 | NULL | 10 |
| 1010 | 韦一笑 | 销售员 | 1006 | 2001-09-08 | 15000 | 0 | 30 |
+-------+-----------+-----------+------+------------+-------+-------+--------+
找出部门编号为10中所有经理,部门编号为30中所有销售员,还有即不是经理又不是销售员但其工资大或等于20000的所有员工详细资料:
mysql> select * from emp where (job='经理' and deptno=10) or (job='销售员' and deptno=30) or (job !='经理' and job!='销售员' and comm>=20000);
+-------+-----------+-----------+------+------------+-------+-------+--------+
| empno | ename | job | mgr | hiredate | sai | comm | deptno |
+-------+-----------+-----------+------+------------+-------+-------+--------+
| 1002 | 黛绮丝 | 销售员 | 1006 | 2001-02-20 | 16000 | 3000 | 30 |
| 1003 | 殷天正 | 销售员 | 1006 | 2001-02-22 | 12500 | 5000 | 30 |
| 1005 | 谢逊 | 销售员 | 1006 | 2001-09-28 | 12500 | 14000 | 30 |
| 1007 | 张飞 | 经理 | 1009 | 2001-09-01 | 24500 | NULL | 10 |
| 1010 | 韦一笑 | 销售员 | 1006 | 2001-09-08 | 15000 | 0 | 30 |
| 1015 | 张三 | 保洁员 | 1001 | 2013-05-01 | 80000 | 50000 | 50 |
+-------+-----------+-----------+------+------------+-------+-------+--------+
无奖金或奖金低于1000的员工:
mysql> select * from emp where comm is null or comm<1000;
+-------+-----------+-----------+------+------------+-------+------+--------+
| empno | ename | job | mgr | hiredate | sai | comm | deptno |
+-------+-----------+-----------+------+------------+-------+------+--------+
| 1001 | 甘宁 | 文员 | 1013 | 2000-12-17 | 8000 | NULL | 20 |
| 1004 | 刘备 | 经理 | 1009 | 2001-04-02 | 29750 | NULL | 20 |
| 1006 | 关羽 | 经理 | 1009 | 2001-05-01 | 28500 | NULL | 30 |
| 1007 | 张飞 | 经理 | 1009 | 2001-09-01 | 24500 | NULL | 10 |
| 1008 | 诸葛亮 | 分析师 | 1004 | 2007-04-19 | 30000 | NULL | 20 |
| 1009 | 曾阿牛 | 董事长 | NULL | 2001-11-17 | 50000 | NULL | 10 |
| 1010 | 韦一笑 | 销售员 | 1006 | 2001-09-08 | 15000 | 0 | 30 |
| 1011 | 周泰 | 文员 | 1006 | 2007-05-23 | 11000 | NULL | 20 |
| 1012 | 程普 | 文员 | 1006 | 2001-12-03 | 9500 | NULL | 30 |
| 1013 | 庞统 | 分析师 | 1004 | 2001-12-03 | 30000 | NULL | 20 |
| 1014 | 黄盖 | 文员 | 1007 | 2002-01-23 | 13000 | NULL | 10 |
+-------+-----------+-----------+------+------------+-------+------+--------+
查询名字由三个字组成的员工:
mysql> select ename from emp where char_length(ename)=3;
+-----------+
| ename |
+-----------+
| 黛绮丝 |
| 殷天正 |
| 诸葛亮 |
| 曾阿牛 |
| 韦一笑 |
+-----------+
查询2000年入职的员工:
mysql> select * from emp where year(hiredate)=2000;
+-------+--------+--------+------+------------+------+------+--------+
| empno | ename | job | mgr | hiredate | sai | comm | deptno |
+-------+--------+--------+------+------------+------+------+--------+
| 1001 | 甘宁 | 文员 | 1013 | 2000-12-17 | 8000 | NULL | 20 |
+-------+--------+--------+------+------------+------+------+--------+
询所有员工详细信息,用编号升序排序:
mysql> select * from emp order by empno;
+-------+-----------+-----------+------+------------+-------+-------+--------+
| empno | ename | job | mgr | hiredate | sai | comm | deptno |
+-------+-----------+-----------+------+------------+-------+-------+--------+
| 1001 | 甘宁 | 文员 | 1013 | 2000-12-17 | 8000 | NULL | 20 |
| 1002 | 黛绮丝 | 销售员 | 1006 | 2001-02-20 | 16000 | 3000 | 30 |
| 1003 | 殷天正 | 销售员 | 1006 | 2001-02-22 | 12500 | 5000 | 30 |
| 1004 | 刘备 | 经理 | 1009 | 2001-04-02 | 29750 | NULL | 20 |
| 1005 | 谢逊 | 销售员 | 1006 | 2001-09-28 | 12500 | 14000 | 30 |
| 1006 | 关羽 | 经理 | 1009 | 2001-05-01 | 28500 | NULL | 30 |
| 1007 | 张飞 | 经理 | 1009 | 2001-09-01 | 24500 | NULL | 10 |
| 1008 | 诸葛亮 | 分析师 | 1004 | 2007-04-19 | 30000 | NULL | 20 |
| 1009 | 曾阿牛 | 董事长 | NULL | 2001-11-17 | 50000 | NULL | 10 |
| 1010 | 韦一笑 | 销售员 | 1006 | 2001-09-08 | 15000 | 0 | 30 |
| 1011 | 周泰 | 文员 | 1006 | 2007-05-23 | 11000 | NULL | 20 |
| 1012 | 程普 | 文员 | 1006 | 2001-12-03 | 9500 | NULL | 30 |
| 1013 | 庞统 | 分析师 | 1004 | 2001-12-03 | 30000 | NULL | 20 |
| 1014 | 黄盖 | 文员 | 1007 | 2002-01-23 | 13000 | NULL | 10 |
| 1015 | 张三 | 保洁员 | 1001 | 2013-05-01 | 80000 | 50000 | 50 |
+-------+-----------+-----------+------+------------+-------+-------+--------+
查询所有员工详细信息,用工资降序排序,如果工资相同使用入职日期升序排序:
mysql> select * from emp order by sai DESC,hiredate asc;
+-------+-----------+-----------+------+------------+-------+-------+--------+
| empno | ename | job | mgr | hiredate | sai | comm | deptno |
+-------+-----------+-----------+------+------------+-------+-------+--------+
| 1015 | 张三 | 保洁员 | 1001 | 2013-05-01 | 80000 | 50000 | 50 |
| 1009 | 曾阿牛 | 董事长 | NULL | 2001-11-17 | 50000 | NULL | 10 |
| 1013 | 庞统 | 分析师 | 1004 | 2001-12-03 | 30000 | NULL | 20 |
| 1008 | 诸葛亮 | 分析师 | 1004 | 2007-04-19 | 30000 | NULL | 20 |
| 1004 | 刘备 | 经理 | 1009 | 2001-04-02 | 29750 | NULL | 20 |
| 1006 | 关羽 | 经理 | 1009 | 2001-05-01 | 28500 | NULL | 30 |
| 1007 | 张飞 | 经理 | 1009 | 2001-09-01 | 24500 | NULL | 10 |
| 1002 | 黛绮丝 | 销售员 | 1006 | 2001-02-20 | 16000 | 3000 | 30 |
| 1010 | 韦一笑 | 销售员 | 1006 | 2001-09-08 | 15000 | 0 | 30 |
| 1014 | 黄盖 | 文员 | 1007 | 2002-01-23 | 13000 | NULL | 10 |
| 1003 | 殷天正 | 销售员 | 1006 | 2001-02-22 | 12500 | 5000 | 30 |
| 1005 | 谢逊 | 销售员 | 1006 | 2001-09-28 | 12500 | 14000 | 30 |
| 1011 | 周泰 | 文员 | 1006 | 2007-05-23 | 11000 | NULL | 20 |
| 1012 | 程普 | 文员 | 1006 | 2001-12-03 | 9500 | NULL | 30 |
| 1001 | 甘宁 | 文员 | 1013 | 2000-12-17 | 8000 | NULL | 20 |
+-------+-----------+-----------+------+------------+-------+-------+--------+
查询每个部门的平均工资:
mysql> select deptno,avg(sai) from emp group by deptno;
+--------+------------+
| deptno | avg(sai) |
+--------+------------+
| 10 | 29166.6667 |
| 20 | 21750.0000 |
| 30 | 15666.6667 |
| 50 | 80000.0000 |
+--------+------------+
4 rows in set (0.00 sec)
查询每个部门的雇员数量:
mysql> select deptno,count(empno) from emp group by deptno;
+--------+--------------+
| deptno | count(empno) |
+--------+--------------+
| 10 | 3 |
| 20 | 5 |
| 30 | 6 |
| 50 | 1 |
+--------+--------------+
mysql> select deptno,count(ename) from emp group by deptno;
+--------+--------------+
| deptno | count(ename) |
+--------+--------------+
| 10 | 3 |
| 20 | 5 |
| 30 | 6 |
| 50 | 1 |
+--------+--------------+
查询每种工作的最高工资、最低工资、人数:
mysql> select max(sai),min(sai) ,count(empno) from emp group by job;
+----------+----------+--------------+
| max(sai) | min(sai) | count(empno) |
+----------+----------+--------------+
| 80000 | 80000 | 1 |
| 30000 | 30000 | 2 |
| 13000 | 8000 | 4 |
| 29750 | 24500 | 3 |
| 50000 | 50000 | 1 |
| 16000 | 12500 | 4 |
+----------+----------+--------------+
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