如何使用mysql分组查询

我有一个列名、EmailId、进程、状态的表，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emailId和所有流程中处于关闭状态的人员的状态-流程1、流程2、流程3

**Output**

EmailId              Status    
orange@fruits.com    Closed

由于橙色的所有过程都已结束，我有上面一行

---

类似地，我希望关闭其进程的表的所有电子邮件ID。

要查找此项，您可以使用聚合计数来查找HAVING子句中的计数=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

如果可能的进程数不完全是3，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目

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)

---

要找到该值，可以使用聚合计数来查找HAVING子句中的计数=3，因此所有三个都是闭合的：

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

如果可能的进程数不完全是3，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目

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)

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：

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：

---

@aprilleocean如果不是您要求的，它会返回什么？如果您也希望返回状态，则没有必要，因为它已知已关闭。如果列表中的进程发生变化，count可能无法工作，例如如果他想检查proc1、proc2、proc4是否已关闭，但某些id具有proc1、proc2、，proc3 closed.@NaveenKumar OP特别要求关闭所有进程，@aprilleocean完全按照上述任何一个示例复制，但在不使用HAVING子句的情况下运行它。它应该返回一行苹果和橘子。With HAVING子句应该只返回橙色。@APRILLEOSEAN那么如果不是您要求的，它会返回什么呢？如果您也希望返回状态，则没有必要，因为它已知已关闭。如果列表中的进程发生变化，计数可能不起作用，例如，如果他想检查proc1、proc2、proc4是否已关闭，但某些id具有proc1，proc2，proc3 closed.@navenkumar OP特别要求关闭所有进程，@aprilleocean复制上述任何一个示例，但在不使用HAVING子句的情况下运行它。它应该返回一行苹果和橘子。With HAVING子句应该只返回橙色。竖起大拇指，它起作用了。谢谢，所以MuchMichael的查询也应该起作用。除非您每封电子邮件的进程数可变，而不是问题所暗示的常数3。@ypercube Michael query不会返回任何记录集Thumbs它成功了，谢谢您，所以MuchMichael的查询也应该成功。除非您的每封电子邮件有可变的进程数，而不是问题所暗示的常数3。@ypercube Michael query不会返回任何记录集