MySQL如何從GROUP BY進行計數

Question

 date | userid | companyid 12.8.14 | 1 | 1 12.8.14 | 2 | 2 12.8.14 | 3 | 1 

我有一張上面的桌子。 通過正常查詢，很容易從表中計算出多少個公司1 。

我的問題是：如果我的查詢是select * from table where companyid = '1' group by date ，那么我如何才能得到mysql_num_row等於2的公司1和userid是1和3 ？

select * from table where companyid = '1' group by date只會返回mysql_num_row等於1並返回12.8.14 | 1 | 1 12.8.14 | 1 | 1

Answer 1

您可以嵌套查詢以獲取公司一條目的總和，然后將該嵌套查詢與外部查詢連接：

SELECT ABB2.*, ABB1.mysql_num_row
FROM `table` AS ABB2
  JOIN 
      (SELECT companyid, COUNT(userid) AS mysql_num_row
      FROM `table`
      GROUP BY companyid) AS ABB1 ON ABB1.companyid = ABB2.companyid
WHERE ABB2.companyid = 1;

例

Answer 2

也嘗試這樣

select *,(select count(*) from table1 where companyid=a.companyid) as count 
from t  as a where companyid=1

Answer 3

你自找的：

select date,companyid,count(*)
from table
where userid = 1
group by date,companyid