分页查询的使用详解

Select column, .. from table_name group by column1, column2;
使用场景：常见于统计场合，计算平均分，统计数据量等
查询每个部门的平均工资
select dept, avg(salary) from emp group by dept;
显示每个部门中的每种岗位的平均工资和最低工资
 select dept, avg(salary), min(salary) from emp group by dept;
select dept,job, avg(salary), min(salary) from emp group by dept,job; 
select dept,job, name,avg(salary), min(salary) from emp group by dept,job,name;

select column, .. from table_name group by column having ...;

select dept, avg(salary) from emp group by dept having avg(salary) <7000;

select *| column, .. from table_name limit [offset] count;

select *from emp limit 3;

select *from emp limit 5, 8;