mysql 数据操作 单表查询 练习

查出所有员工的名字，薪资,格式为

<名字:egon>,<薪资:3000>

mysql> select concat('<姓名:',name,'>') as name_info , concat('<薪资:',salary,'>') as salary_info  from employee;
+---------------------+---------------------+
| name_info           | salary_info         |
+---------------------+---------------------+
| <姓名:alex>         | <薪资:1000000.31>   |
| <姓名:yuanhao>      | <薪资:3500.00>      |
| <姓名:liwenzhou>    | <薪资:2100.00>      |
| <姓名:jingliyang>   | <薪资:9000.00>      |
| <姓名:jinxin>       | <薪资:30000.00>     |
| <姓名:成龙>         | <薪资:10000.00>     |
| <姓名:歪歪>         | <薪资:3000.13>      |
| <姓名:丫丫>         | <薪资:2000.35>      |
| <姓名:丁丁>         | <薪资:1000.37>      |
| <姓名:星星>         | <薪资:3000.29>      |
| <姓名:格格>         | <薪资:4000.33>      |
| <姓名:张野>         | <薪资:10000.13>     |
| <姓名:程咬金>       | <薪资:20000.00>     |
| <姓名:程咬银>       | <薪资:19000.00>     |
| <姓名:程咬铜>       | <薪资:18000.00>     |
| <姓名:程咬铁>       | <薪资:17000.00>     |
+---------------------+---------------------+
16 rows in set (0.00 sec)

2
 查出所有的岗位（去掉重复）

mysql> select distinct post from employee;
+-----------+
| post      |
+-----------+
| teacher   |
| sale      |
| operation |
+-----------+
3 rows in set (0.00 sec)

3 查出所有员工名字，以及他们的年薪,年薪的字段名为annual_year

mysql> select name,salary*12 as annual_year from employee;
+------------+-------------+
| name       | annual_year |
+------------+-------------+
| alex       | 12000003.72 |
| yuanhao    |    42000.00 |
| liwenzhou  |    25200.00 |
| jingliyang |   108000.00 |
| jinxin     |   360000.00 |
| 成龙       |   120000.00 |
| 歪歪       |    36001.56 |
| 丫丫       |    24004.20 |
| 丁丁       |    12004.44 |
| 星星       |    36003.48 |
| 格格       |    48003.96 |
| 张野       |   120001.56 |
| 程咬金     |   240000.00 |
| 程咬银     |   228000.00 |
| 程咬铜     |   216000.00 |
| 程咬铁     |   204000.00 |
+------------+-------------+
16 rows in set (0.00 sec)