MySQL-SQL基础1
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#插入
mysql> insert into emp values('zzx1','2002-03-09','2009-04-03','2001',3,22);
Query OK, 1 row affected (0.00 sec)
mysql> insert into emp values('ttx2','20023-04-10','2010-03-04','2002',4,23);
ERROR 1292 (22007): Incorrect date value: '20023-04-10' for column 'birth' at row 1
mysql> insert into emp values('ttx2','2023-04-10','2010-03-04','2002',4,23);
Query OK, 1 row affected (0.00 sec)
mysql> select * from emp;
+-------+------------+------------+---------+--------+------+
| ename | birth | hirdate | sal | deptno | age1 |
+-------+------------+------------+---------+--------+------+
| zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 |
| zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 |
| ttx2 | 2023-04-10 | 2010-03-04 | 2002.00 | 4 | 23 |
+-------+------------+------------+---------+--------+------+
3 rows in set (0.00 sec)
#更新
mysql> update emp set sal=4000 where ename='ttx2';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> select * from emp;
+-------+------------+------------+---------+--------+------+
| ename | birth | hirdate | sal | deptno | age1 |
+-------+------------+------------+---------+--------+------+
| zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 |
| zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 |
| ttx2 | 2023-04-10 | 2010-03-04 | 4000.00 | 4 | 23 |
+-------+------------+------------+---------+--------+------+
3 rows in set (0.00 sec)
mysql> select distinct deptno from emp;
+--------+
| deptno |
+--------+
| 1 |
| 3 |
| 4 |
+--------+
3 rows in set (0.01 sec)
#查询
mysql> select * from emp where deptno=1;
+-------+------------+------------+---------+--------+------+
| ename | birth | hirdate | sal | deptno | age1 |
+-------+------------+------------+---------+--------+------+
| zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 |
+-------+------------+------------+---------+--------+------+
1 row in set (0.00 sec)
mysql> select * from emp where deptno=2;
Empty set (0.00 sec)
mysql> select * from emp where deptno=3;
+-------+------------+------------+---------+--------+------+
| ename | birth | hirdate | sal | deptno | age1 |
+-------+------------+------------+---------+--------+------+
| zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 |
+-------+------------+------------+---------+--------+------+
1 row in set (0.00 sec)
mysql> select * from emp order by sal;
+-------+------------+------------+---------+--------+------+
| ename | birth | hirdate | sal | deptno | age1 |
+-------+------------+------------+---------+--------+------+
| zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 |
| zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 |
| ttx2 | 2023-04-10 | 2010-03-04 | 4000.00 | 4 | 23 |
+-------+------------+------------+---------+--------+------+
3 rows in set (0.00 sec)
mysql> select * from emp order by deptno;
+-------+------------+------------+---------+--------+------+
| ename | birth | hirdate | sal | deptno | age1 |
+-------+------------+------------+---------+--------+------+
| zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 |
| zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 |
| ttx2 | 2023-04-10 | 2010-03-04 | 4000.00 | 4 | 23 |
+-------+------------+------------+---------+--------+------+
3 rows in set (0.00 sec)
#查询排序
mysql> select * from emp order by deptno,sal desc;
+-------+------------+------------+---------+--------+------+
| ename | birth | hirdate | sal | deptno | age1 |
+-------+------------+------------+---------+--------+------+
| zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 |
| zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 |
| ttx2 | 2023-04-10 | 2010-03-04 | 4000.00 | 4 | 23 |
+-------+------------+------------+---------+--------+------+
3 rows in set (0.00 sec)
#分页查询
mysql> select * from emp order by sal limit 3;
+-------+------------+------------+---------+--------+------+
| ename | birth | hirdate | sal | deptno | age1 |
+-------+------------+------------+---------+--------+------+
| zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 |
| zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 |
| ttx2 | 2023-04-10 | 2010-03-04 | 4000.00 | 4 | 23 |
+-------+------------+------------+---------+--------+------+
3 rows in set (0.00 sec)
mysql> select * from emp order by sal limit 1,3;
+-------+------------+------------+---------+--------+------+
| ename | birth | hirdate | sal | deptno | age1 |
+-------+------------+------------+---------+--------+------+
| zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 |
| ttx2 | 2023-04-10 | 2010-03-04 | 4000.00 | 4 | 23 |
+-------+------------+------------+---------+--------+------+
2 rows in set (0.00 sec)
#查询表总数
mysql> select count(1) from emp;
+----------+
| count(1) |
+----------+
| 3 |
+----------+
1 row in set (0.00 sec)
#针对emp表进行统计deptno的个数
mysql> select deptno,count(1) from emp group by deptno;
+--------+----------+
| deptno | count(1) |
+--------+----------+
| 1 | 1 |
| 3 | 1 |
| 4 | 1 |
+--------+----------+
3 rows in set (0.00 sec)
#对ename排序并计算
mysql> select ename,count(1) from emp group by ename;
+-------+----------+
| ename | count(1) |
+-------+----------+
| ttx2 | 1 |
| zzx1 | 2 |
+-------+----------+
2 rows in set (0.00 sec)
#对sal排序并计算
mysql> select sal,count(1) from emp group by sal;
+---------+----------+
| sal | count(1) |
+---------+----------+
| 2000.00 | 1 |
| 2001.00 | 1 |
| 4000.00 | 1 |
+---------+----------+
3 rows in set (0.00 sec)
#对age1排序并计算
mysql> select age1,count(1) from emp group by age1;
+------+----------+
| age1 | count(1) |
+------+----------+
| 21 | 1 |
| 22 | 1 |
| 23 | 1 |
+------+----------+
3 rows in set (0.01 sec)
#查看emp表结构
mysql> desc emp;
+---------+---------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------+---------------+------+-----+---------+-------+
| ename | varchar(20) | YES | | NULL | |
| birth | date | YES | | NULL | |
| hirdate | date | YES | | NULL | |
| sal | decimal(10,2) | YES | | NULL | |
| deptno | int(2) | YES | | NULL | |
| age1 | int(4) | YES | | NULL | |
+---------+---------------+------+-----+---------+-------+
6 rows in set (0.00 sec)
#对birth列排序并计算
mysql> select birth,count(1) from emp group by birth;
+------------+----------+
| birth | count(1) |
+------------+----------+
| 2000-01-01 | 1 |
| 2002-03-09 | 1 |
| 2023-04-10 | 1 |
+------------+----------+
3 rows in set (0.00 sec)
#对hirdate列排序并计算
mysql> select hirdate,count(1) from emp group by hirdate;
+------------+----------+
| hirdate | count(1) |
+------------+----------+
| 2000-01-01 | 1 |
| 2009-04-03 | 1 |
| 2010-03-04 | 1 |
+------------+----------+
3 rows in set (0.00 sec)
#统计部门人数同时统计总人数
mysql> select deptno,count(1) from emp group by deptno with rollup;
+--------+----------+
| deptno | count(1) |
+--------+----------+
| 1 | 1 |
| 3 | 1 |
| 4 | 1 |
| NULL | 3 |
+--------+----------+
4 rows in set (0.00 sec)
#统计ename同时统计总人数
mysql> select ename,count(1) from emp group by ename with rollup;
+-------+----------+
| ename | count(1) |
+-------+----------+
| ttx2 | 1 |
| zzx1 | 2 |
| NULL | 3 |
+-------+----------+
3 rows in set (0.00 sec)
#统计出生人数同时统计总人数
mysql> select birth,count(1) from emp group by birth with rollup;
+------------+----------+
| birth | count(1) |
+------------+----------+
| 2000-01-01 | 1 |
| 2002-03-09 | 1 |
| 2023-04-10 | 1 |
| NULL | 3 |
+------------+----------+
4 rows in set (0.00 sec)
#统计录用时间同时统计总人数
mysql> select hirdate,count(1) from emp group by hirdate with rollup;
+------------+----------+
| hirdate | count(1) |
+------------+----------+
| 2000-01-01 | 1 |
| 2009-04-03 | 1 |
| 2010-03-04 | 1 |
| NULL | 3 |
+------------+----------+
4 rows in set (0.00 sec)
#统计薪资数同时统计总人数
mysql> select sal,count(1) from emp group by sal with rollup;
+---------+----------+
| sal | count(1) |
+---------+----------+
| 2000.00 | 1 |
| 2001.00 | 1 |
| 4000.00 | 1 |
| NULL | 3 |
+---------+----------+
4 rows in set (0.00 sec)
#统计年龄同时统计总人数
mysql> select age1,count(1) from emp group by age1 with rollup;
+------+----------+
| age1 | count(1) |
+------+----------+
| 21 | 1 |
| 22 | 1 |
| 23 | 1 |
| NULL | 3 |
+------+----------+
4 rows in set (0.00 sec)
#统计部门大于0的部门
mysql> select deptno,count(1) from emp group by deptno having count(1)>0;
+--------+----------+
| deptno | count(1) |
+--------+----------+
| 1 | 1 |
| 3 | 1 |
| 4 | 1 |
+--------+----------+
3 rows in set (0.00 sec)
#计算薪资总数、最高薪资、最低薪资
mysql> select sum(sal),max(sal),min(sal) from emp;
+----------+----------+----------+
| sum(sal) | max(sal) | min(sal) |
+----------+----------+----------+
| 8001.00 | 4000.00 | 2000.00 |
+----------+----------+----------+
1 row in set (0.00 sec)
#联表查询
mysql> create table dept(deptno int(10),deptname varchar(20));
Query OK, 0 rows affected (0.01 sec)
mysql> insert into dept values(1,'tech');
Query OK, 1 row affected (0.00 sec)
mysql> insert into dept values(2,'sale');
Query OK, 1 row affected (0.00 sec)
mysql> insert into dept values(3,'hr');
Query OK, 1 row affected (0.00 sec)
mysql> select ename from emp where emp.deptno=emp.deptno;
+-------+
| ename |
+-------+
| zzx1 |
| zzx1 |
| ttx2 |
+-------+
3 rows in set (0.00 sec)
#左连接查询
mysql> select ename,deptname from emp left join dept on emp.deptno=dept.deptno;
+-------+----------+
| ename | deptname |
+-------+----------+
| zzx1 | tech |
| zzx1 | hr |
| ttx2 | NULL |
+-------+----------+
3 rows in set (0.00 sec)
#右连接查询
mysql> select ename,deptname from dept right join emp on dept.deptno=emp.deptno;
+-------+----------+
| ename | deptname |
+-------+----------+
| zzx1 | tech |
| zzx1 | hr |
| ttx2 | NULL |
+-------+----------+
3 rows in set (0.00 sec)
mysql> select * from emp;
+-------+------------+------------+---------+--------+------+
| ename | birth | hirdate | sal | deptno | age1 |
+-------+------------+------------+---------+--------+------+
| zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 |
| zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 |
| ttx2 | 2023-04-10 | 2010-03-04 | 4000.00 | 4 | 23 |
+-------+------------+------------+---------+--------+------+
3 rows in set (0.00 sec)
mysql> select * from dept;
+--------+----------+
| deptno | deptname |
+--------+----------+
| 1 | tech |
| 2 | sale |
| 3 | hr |
+--------+----------+
3 rows in set (0.01 sec)
mysql> insert into dept values(4,'sl');
Query OK, 1 row affected (0.00 sec)
mysql> insert into emp values('ssss','2019-01-01','2018-01-01',5000,2,24);
Query OK, 1 row affected (0.00 sec)
mysql> select * from dept;
+--------+----------+
| deptno | deptname |
+--------+----------+
| 1 | tech |
| 2 | sale |
| 3 | hr |
| 4 | sl |
+--------+----------+
4 rows in set (0.00 sec)
mysql> select * from emp;
+-------+------------+------------+---------+--------+------+
| ename | birth | hirdate | sal | deptno | age1 |
+-------+------------+------------+---------+--------+------+
| zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 |
| zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 |
| ttx2 | 2023-04-10 | 2010-03-04 | 4000.00 | 4 | 23 |
| ssss | 2019-01-01 | 2018-01-01 | 5000.00 | 2 | 24 |
+-------+------------+------------+---------+--------+------+
4 rows in set (0.00 sec)
mysql> select ename,deptname from emp left join dept on emp.deptno=dept.deptno;
+-------+----------+
| ename | deptname |
+-------+----------+
| zzx1 | tech |
| ssss | sale |
| zzx1 | hr |
| ttx2 | sl |
+-------+----------+
4 rows in set (0.00 sec)
mysql> select ename,deptname from dept right join emp on dept.deptno=emp.deptno;
+-------+----------+
| ename | deptname |
+-------+----------+
| zzx1 | tech |
| ssss | sale |
| zzx1 | hr |
| ttx2 | sl |
+-------+----------+
4 rows in set (0.00 sec)
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