mysql> create table t_worker(
-> department_id int(11) not null comment '部门号',
-> worker_id int(11) primary key not null comment '职工号',
-> worker_date date not null comment '工作时间',
-> wages float(8,2) not null comment '工资',
-> politics varchar(10) not null default '群众' comment '政治面貌',
-> name varchar(20) not null comment '姓名',
-> borth_date date not null comment '出生日期');
mysql> insert into t_worker values (101,1001,'2015-5-4',7500.00,'群众','张春燕','1990-7-1');
Query OK, 1 row affected (0.01 sec)
mysql> insert into t_worker values (101,1002,'2019-2-6',5200.00,'团员','李名博','19
97-2-8');
Query OK, 1 row affected (0.01 sec)
mysql> insert into t_worker values (102,1003,'2008-1-4',10500.00,'党员','王博涵','1
983-6-8');
Query OK, 1 row affected (0.01 sec)
mysql> insert into t_worker values (102,1004,'2016-10-10',5500.00,'群众','赵小军','
1994-9-5');
Query OK, 1 row affected (0.01 sec)
mysql> insert into t_worker values (102,1005,'2014-4-1',8800.00,'党员','钱有财','19
92-12-30');
Query OK, 1 row affected (0.01 sec)
mysql> insert into t_worker values (103,1006,'2019-5-5',5500.00,'党员','孙菲菲','19
96-9-2');
Query OK, 1 row affected (0.01 sec)
（1）mysql> select * from t_worker;
（2）mysql> select distinct department_id from t_worker;
（3）mysql> select count(1) from t_worker;
（4）mysql> select max(wages) , min(wages) from t_worker;
（5）mysql> select round(avg(wages),2),sum(wages) from t_worker;
（6）mysql> create table work_date(worker_id int(11) primary key not null comment'职工号',name varchar(20) not null comment'姓名', worker_date date not null comment'工作时间');
mysql> desc work_date;
（7）mysql> select year(now())-year( borth_date) from t_worker
-> where politics='党员';
（8）mysql> select name from t_worker
-> where wages between 4000 and 8000;
（9）mysql> select name from t_worker
-> where name like '孙%' or name like '李%';
（10）mysql> select worker_id,name from t_worker
-> where department_id in (102,103) and politics!='党员';
（11）mysql> select * from t_worker
-> order by borth_date ;
（12）mysql> select worker_id,name from t_worker order by wages desc limit 1,3;
（13）mysql> select count(1) from t_worker
-> where politics='党员';
（14）mysql> select sum(wages),round(avg(wages),2) from t_worker;
（15）mysql> select department_id,count(1) from t_worker
-> group by department_id
-> having count(1)>=3;
