Question

我有一个表格，列名为Name，EmailId，Process，Status，如下所示。

**Input**

   Name       EmailId                Process      Status    
   apple1     apple@fruits.com       process1     Closed
   apple2     apple@fruits.com       process2     In Progress
   apple3     apple@fruits.com       process3     Complete      
   orange1    orange@fruits.com      process1     Closed
   orange2    orange@fruits.com      process2     Closed
   oran       orange@fruits.com      process3     Closed
   mango1     mango@fruits.com       process1     To Start

现在我想要的是所有流程 - Process1，process2，流程3的状态已关闭的人员的emailId和状态

**Output**

EmailId              Status    
orange@fruits.com    Closed

由于橙色的所有过程都已关闭，我有上面的行同样，我希望获得表格的所有电子邮件ID，其过程已关闭。

Answer 1

要找到这个，您可以使用聚合COUNT()在HAVING子句中找到count = 3，因此所有三个都已关闭：

SELECT
  EmailId,
  /* How many different processes are closed per EmailId */
  COUNT(DISTINCT Process) AS numclosed
FROM
  yourtable
WHERE Status = 'Closed'
GROUP BY EmailId
/* Return only those with 3 processes closed */
HAVING numclosed = 3

如果可能进程的数量不完全是3并且您需要考虑所有进程，我相信您可以使用HAVING子句中的子查询来查找可能进程的实际数量

SELECT
  EmailId,
  COUNT(DISTINCT Process) AS numclosed
FROM
  yourtable
WHERE Status = 'Closed'
GROUP BY EmailId
/* Compare the number closed for this EmailId against the number of possible Process values in the table */
HAVING numclosed = (SELECT COUNT(DISTINCT Process) FROM yourtable)

Answer 2

另一种方式：

SELECT 
    EmailId
FROM
    tableX AS t
GROUP BY 
    EmailId
HAVING
    COUNT( CASE WHEN Status <> 'Closed'
             THEN 1 
           END
         ) = 0 ;

或：

SELECT 
    t.EmailId
FROM
    ( SELECT DISTINCT EmailId
      FROM tableX 
    ) AS t
  LEFT JOIN
    tableX AS tt
      ON  tt.EmailId = t.EmailId
      AND tt.Status <> 'Closed'
WHERE
    tt.EmailId IS NULL ;

如何通过查询使用mysql组

2 个答案: