在mysql查詢中計算相同的值

Question

所以我有一個像

SELECT * FROM `catalog` WHERE `id` IN ('2','2','3','3','3');

並且這只返回2行，ID為2和3.有可能使它返回5行（2個ID為“2”，3個ID為“3”）或者將計數添加為新列？

Answer 1

不確定為什么你會想要做這樣的事情，但不是使用'in'子句，你可以使用內部查詢：

select *
from `catalog` c,
(
    select 2 ids
    union all
    select 2
    union all
    select 3
    union all
    select 3
    union all
    select 3
) k
where c.id = k.ids

Answer 2

嘗試這樣的事情：

SELECT t.p,count(*)  FROM 
    catalog, 
    (SELECT 2 as id
    Union all select 2 as id
    Union all select 3 as id
    Union all select 3 as id
    Union all select 3 as id)as t 
where catalog.id = t.id

Answer 3

可以使用臨時表來完成：

create temporary table arrayt (id int);
insert into arrayt values  ('2'),('2'),('3'),('3'),('3');
select catalog.* from arrayt a LEFT JOIN catalog on (a.id=catalog.id);

如果你需要數數

select count(catalog.id) as count,catalog.id as id from arrayt a LEFT JOIN catalog on (a.id=catalog.id) group by catalog.id;