SQL的聚合函數與排序

count 函數

語法：

Select count(*) count(列名) from table_name [where where_defination];Select count(id) from stu;Select count(name) from stu where math > 90;select count (name) from stu where chines+math+English> 250;

sum函數

Select sum (列名) from stu [where where_defination];
Select sum (列名),sum(列名), sum(列名) from stu [where where_definition];
Select sum (列名)+sum(列名)+ sum(列名) from stu [where where_definition];
Select sum (列名)+sum(列名)+sum(列名) as 總分 from stu [where where_definition];
Select sum (列名)/count(name) from stu [where where_defination];
Select avg(math) from stu;
Select avg(math + chines + english) from stu;
Select max min(列名) from stu;
Select max(math + chines + english) from stu;
Select min(math + chines + english) from stu;

對查詢結果排序

使用order by 子句排序查詢結果

Select column1, column2, column3 from table order by column asc desc

order by指排序的列，也可以是select后面指定的列名

order by 子句應位于select 語句的結尾

Select name, math from stu order by math;
select name, math+english+chines from stu order by math+english+chines desc;
select name, math+english+chines from stu where name like 'zhang%' order by math+english+chines desc;

相信看了本文案例你已經掌握了方法，更多精彩請關注php中文網其它相關文章！

推薦閱讀：

分頁查詢的使用詳解

JS的日期相關函數使用詳解

以上就是SQL的聚合函數與排序的詳細內容，更多請關注php中文網其它相關文章！