2

次のようなクエリがあります。

SELECT COUNT(id) AS user_list FROM tbl_users
WHERE (enrolled = 1 AND age >=15 AND age < 20)
OR (enrolled = 1 AND age >=20 AND age < 25)
OR (enrolled = 1 AND age >=25 AND age < 30)
OR (enrolled = 1 AND age >=30)

1 つの行と 1 つのテーブルの where 条件ごとに結果を返すにはどうすればよいですか。

user_list
---------
   18    --(enrolled = 1 AND age >=15 AND age < 20)
   12    --(enrolled = 1 AND age >=20 AND age < 25)
   22    --(enrolled = 1 AND age >=25 AND age < 30) 
   56    --(enrolled = 1 AND age >=30)
4

6 に答える 6

1

この方法を試してください

create table t (list1 int,list2 int,list3 int,list4 int)

insert into t
SELECT 
SUM(case when age >=15 AND age < 20 then 1 else 0 end) AS user_list1,
SUM(case when age >=20 AND age < 25 then 1 else 0 end) AS user_list2,
SUM(case when age >=25 AND age < 30 then 1 else 0 end) AS user_list3,
SUM(case when age >=15 AND age < 20 then 1 else 0 end) AS user_list4
FROM tbl_users
WHERE enrolled = 1 ;

select list1 from t union all
select list2 from t union all
select list3 from t union all
select list4 from t
于 2013-10-30T10:31:32.377 に答える
0

1 つの複雑なクエリではなく 4 つの単純なクエリを使用しても、パフォーマンスに問題はありません。

于 2013-10-30T10:26:43.603 に答える