msql 統計函數 and 分組統計

標籤：max   sele   min   bsp   group   sql   統計   排序   msql   

 平均數

select  avg(shop_price) from goods;

求最大最小

select min(shop_price) from goods;

select max(shop_price) from goods;

求行數

select count(*) from goods;

 

分組統計

group 是需要耗費資源的  會有排序

slect cat_id,avg(shop_price) from goods group by cat_id;

select cat_id,count(*) from goods group by cat_id;

select cat_id,max(good_price)) from goods group by cat_id;

 

msql 統計函數 and 分組統計