MYSQL第二次作业

（1）

mysql> select * from t_worker;
+---------------+-----------+-------------+----------+----------+-----------+------------+
| department_id | worker_id | worker_date | wages    | politics | name      | borth_date |
+---------------+-----------+-------------+----------+----------+-----------+------------+
|           101 |      1001 | 2015-05-04  |  7500.00 | 群众     | 张春燕    | 1990-07-01 |
|           101 |      1002 | 2019-02-06  |  5200.00 | 团员     | 李名博    | 1997-02-08 |
|           102 |      1003 | 2008-01-04  | 10500.00 | 党员     | 王博涵    | 1983-06-08 |
|           102 |      1004 | 2016-10-10  |  5500.00 | 群众     | 赵小军    | 1994-09-05 |
|           102 |      1005 | 2014-04-01  |  8800.00 | 党员     | 钱有才    | 1992-12-30 |
|           103 |      1006 | 2019-05-05  |  5500.00 | 党员     | 孙菲菲    | 1996-09-02 |
+---------------+-----------+-------------+----------+----------+-----------+------------+
6 rows in set (0.00 sec)

（2）

mysql> select distinct department_id from t_worker;
+---------------+
| department_id |
+---------------+
|           101 |
|           102 |
|           103 |
+---------------+
3 rows in set (0.00 sec)

（3）

mysql> select count(*) as total_worker from t_worker;
+--------------+
| total_worker |
+--------------+
|            6 |
+--------------+
1 row in set (0.01 sec)

（4）

mysql> select max(wages) as max_wages, min(wages) as min_wages from t_worker;
+-----------+-----------+
| max_wages | min_wages |
+-----------+-----------+
|  10500.00 |   5200.00 |
+-----------+-----------+
1 row in set (0.00 sec)

（5）

mysql> select avg(wages) as avg_wages, sum(wages) as total_wages from t_worker;
+-------------+-------------+
| avg_wages   | total_wages |
+-------------+-------------+
| 7166.666667 |    43000.00 |
+-------------+-------------+
1 row in set (0.00 sec)

（6）

mysql> create table work_date_table as select worker_id, name, worker_date from t_worker;
Query OK, 6 rows affected (0.03 sec)
Records: 6  Duplicates: 0  Warnings: 0

（7）

mysql> select timestampdiff(year, borth_date, curdate()) as age
    -> from t_worker
    -> where politics = '党员';
+------+
| age  |
+------+
|   42 |
|   32 |
|   29 |
+------+
3 rows in set (0.00 sec)

（8）

mysql> select name from t_worker where wages between 4000 and 8000;
+-----------+
| name      |
+-----------+
| 张春燕    |
| 李名博    |
| 赵小军    |
| 孙菲菲    |
+-----------+
4 rows in set (0.00 sec)

（9）

mysql> select name from t_worker where name like '孙%' or name like '李%';
+-----------+
| name      |
+-----------+
| 李名博    |
| 孙菲菲    |
+-----------+
2 rows in set (0.00 sec)

（10）

mysql> select worker_id, name from t_worker
    -> where department_id in (102, 103) and politics!= '党员';
+-----------+-----------+
| worker_id | name      |
+-----------+-----------+
|      1004 | 赵小军    |
+-----------+-----------+
1 row in set (0.00 sec)

（11）

mysql> select * from t_worker order by borth_date;
+---------------+-----------+-------------+----------+----------+-----------+------------+
| department_id | worker_id | worker_date | wages    | politics | name      | borth_date |
+---------------+-----------+-------------+----------+----------+-----------+------------+
|           102 |      1003 | 2008-01-04  | 10500.00 | 党员     | 王博涵    | 1983-06-08 |
|           101 |      1001 | 2015-05-04  |  7500.00 | 群众     | 张春燕    | 1990-07-01 |
|           102 |      1005 | 2014-04-01  |  8800.00 | 党员     | 钱有才    | 1992-12-30 |
|           102 |      1004 | 2016-10-10  |  5500.00 | 群众     | 赵小军    | 1994-09-05 |
|           103 |      1006 | 2019-05-05  |  5500.00 | 党员     | 孙菲菲    | 1996-09-02 |
|           101 |      1002 | 2019-02-06  |  5200.00 | 团员     | 李名博    | 1997-02-08 |
+---------------+-----------+-------------+----------+----------+-----------+------------+
6 rows in set (0.00 sec)

（12）

mysql> select worker_id, name from t_worker order by wages desc limit 3;
+-----------+-----------+
| worker_id | name      |
+-----------+-----------+
|      1003 | 王博涵    |
|      1005 | 钱有才    |
|      1001 | 张春燕    |
+-----------+-----------+
3 rows in set (0.00 sec)

（13）

mysql> select department_id, count(*) as party_member_count
    -> from t_worker
    -> where politics = '党员'
    -> group by department_id;
+---------------+--------------------+
| department_id | party_member_count |
+---------------+--------------------+
|           102 |                  2 |
|           103 |                  1 |
+---------------+--------------------+
2 rows in set (0.00 sec)

（14）

mysql> select department_id, sum(wages) as total_department_wages, round(avg(wages), 2) as avg_department_wages
    -> from t_worker
    -> group by department_id;
+---------------+------------------------+----------------------+
| department_id | total_department_wages | avg_department_wages |
+---------------+------------------------+----------------------+
|           101 |               12700.00 |                 6350 |
|           102 |               24800.00 |              8266.67 |
|           103 |                5500.00 |                 5500 |
+---------------+------------------------+----------------------+
3 rows in set (0.00 sec)

（15）

mysql> select department_id, count(*) as total_count
    -> from t_worker
    -> group by department_id
    -> having total_count >= 3;
+---------------+-------------+
| department_id | total_count |
+---------------+-------------+
|           102 |           3 |
+---------------+-------------+
1 row in set (0.00 sec)