SQL Server中的计数和分组依据

我有一个查询，它进行了几个连接，但我想做一个

计数

，按照现在的方式，每个人的计数都是1。我做错了什么，让它变得如此重要？谢谢

SELECT
  UserColder.ContactName,
  CountryUser.[User ID],
  COUNT(Country.Name) As num,
  Country.Name,
  Country.ID
FROM
  dbo.Country
  INNER JOIN dbo.CountryUser
    ON Country.ID = CountryUser.[Foreign ID]
  INNER JOIN dbo.UserColder
    ON CountryUser.[User ID] = UserColder.ID
WHERE
  EXISTS
  (SELECT
    NULL
   FROM
    CountryUser CU2
   WHERE
    CU2.[Foreign ID] = CountryUser.[Foreign ID]
    AND CU2.[User ID] <> CountryUser.[User ID])
    GROUP BY UserColder.ContactName, CountryUser.[User ID], Country.Name, Country.ID

---

因此，仅次于美国的应该是3个，加拿大2个，中国1个。

要计算每个国家的用户数，a是一种可能性。可能是这样的：

SELECT u.ContactName
      ,cu.[User ID]
      ,c.Name
      ,c.ID
      ,count(*) OVER (PARTITION BY c.ID) AS users_in_this_country
FROM   dbo.Country     AS  c
JOIN   dbo.CountryUser AS cu ON c.ID = cu.[Foreign ID]
JOIN   dbo.UserColder  AS  u ON cu.[User ID] = u.ID
WHERE  EXISTS (
    SELECT *
    FROM   CountryUser AS cu2
    WHERE  cu2.[Foreign ID] = cu.[Foreign ID]
    AND    cu2.[User ID] <> cu.[User ID])
    )

;With cte AS (
   < query from above >
   )
SELECT *
FROM   cte
WHERE  users_in_this_country > 1

---

您需要在外部查询的select部分创建一个子查询，并将其连接到外部查询。例如，它应该看起来像这样。希望这能有所帮助

SELECT
  UserColder.ContactName,
  CountryUser.[User ID],
  (SELECT COUNT(C2.Name) FROM dbo.Country C2 INNER JOIN dbo.CountryUser CU2
    ON C2.ID = CU2.[Foreign ID]
    WHERE UserColder.ID = CU2.[User ID])  As num,
  Country.Name,
  Country.ID
FROM
  dbo.Country
  INNER JOIN dbo.CountryUser
    ON Country.ID = CountryUser.[Foreign ID]
  INNER JOIN dbo.UserColder
    ON CountryUser.[User ID] = UserColder.ID

---

你能提供一些说明结果数据吗？您想根据其他列计算哪一列的数量？您想计算的具体数量是多少？如果您想计算每个名称的数量，您不应该按

Country.Name

对查询进行分组吗？我想你基本上有一组1人。太好了！谢谢你的帮助！最后一个问题如何按用户筛选此国家/地区>1？谢谢@贾斯汀：我在上面又加了一个答案。

SELECT
  UserColder.ContactName,
  CountryUser.[User ID],
  (SELECT COUNT(C2.Name) FROM dbo.Country C2 INNER JOIN dbo.CountryUser CU2
    ON C2.ID = CU2.[Foreign ID]
    WHERE UserColder.ID = CU2.[User ID])  As num,
  Country.Name,
  Country.ID
FROM
  dbo.Country
  INNER JOIN dbo.CountryUser
    ON Country.ID = CountryUser.[Foreign ID]
  INNER JOIN dbo.UserColder
    ON CountryUser.[User ID] = UserColder.ID