Oracle 中實現交叉表 查詢

交叉表能清晰準確的反映出數據的關係，因此在實際應用中也經常見到，但是作爲二維表格的關係型數據在統計時不能簡單的通過查詢來實現，這裏以Oracle 爲例簡單介紹一下交叉表的查詢：

百度模板圖片：

• 一、創建數據表

--建表
create table tbUser(Gender varchar2(10),Handness varchar2(30));
--插入模擬數據
declare
 i integer;
begin
  for i in 1..4 loop
    insert into tbUser(Gender,Handness)
    values('Female','Left');
  end loop;
  commit;
end;

• 二、通過查詢生成交叉表

with t1 as(
select gender,sum(left) left,sum(right) right,sum(total) total from(
select gender,sum(male) male,sum(female) female,sum(Left) left, sum(Right) right,(sum(male)+sum(female)) total from(
select gender,decode(gender,'Male',1,0) male,decode(gender,'Female',1,0) female,decode(handness,'Left',1,0) Left,decode(handness,'Right',1,0) Right
 from tbUser)
 group by gender,left,right
 )
group by gender)
select gender,right,left,total from t1
union all 
select 'total' gender,sum(right) right,sum(left) left,sum(total) total from t1;

效果：