学习mysql之后的一点总结(基础)_MySQL

2.查询数据表中的数据；

select selection_list select * /columns

from table_list from table1/table2

where primary_constraint

group by grouping_columns

order by sorting_colomns desc降序 select * from table order by id desc;

having second_constraint

limit count select * from table where id limit 1,4;

2 常用的统计函数：avg(字段),sum(字段),count(字段),min(字段),

select sum(字段2) as 别名 ，字段1 from table group by 字段1；

3 算数运算，字符串，以及逻辑运算构造表达式：select * (price*0.8) as '80%' from table;打八折bitsCN.com