Question

我希望从vusers中拆分包含以下数据的行

vusers     branchuserid
name       12,13,10
putra      10,11,9
eko        5
gilang     7,8

tbl_branch

   ID     branch
----------------------
    5     new york
    6     bandung
    7     jakarta
    8     sulawesi
    9     makasar
    10    jalan
    11    menuju
    12    kebenaran
    13    sulit

我想从tbl_branch获取ID，其中ID包含branchuserid。

我的查询有问题。我想获得JOIN语句的价值，但它对我不起作用。这是我的查询

 SELECT vUsers.userID, tbl_branch.branch  FROM vUsers JOIN tbl_branch
     ON (SELECT Split.Data.value('.', 'VARCHAR(100)') AS BranchID FROM
     (Select CAST('<M>' + REPLACE(userAccessbranch,',', '</M><M>')+ '</M>'
     AS XML) AS String FROM vUsers) AS Data CROSS APPLY String.nodes ('/M')
     AS Split(Data)) = tbl_branch.ID

Answer 1

要确保从子查询中只获取一条记录，您只能使用TOP 1

返回一条记录

SELECT vUsers.userID, tbl_branch.branch
FROM vUsers
JOIN tbl_branch ON (SELECT TOP 1 Split.Data.value('.', 'VARCHAR(100)') AS BranchID
                     FROM (Select TOP 1 CAST('<M>' + REPLACE(userAccessbranch,',', '</M><M>')+ '</M>'AS XML) AS String
                           FROM vUsers) AS Data
                     CROSS APPLY String.nodes ('/M') AS Split(Data)) = tbl_branch.ID

Answer 2

基本上，您的连接表达式具有以下模式：

row set = scalar value

其中 row set 是您的(SELECT Split.Data.value...)子查询和 scalar value ，tbl_branch.ID。

解决此问题的最简单方法是翻转谓词的边，并将=替换为IN或= ANY。所以，它可能是

ON tbl_branch.ID IN (SELECT Split.Data.value...)

或

ON tbl_branch.ID = ANY (SELECT Split.Data.value...)

但是，数组不是SQL（或特别是Transact-SQL）最强大的一面。该语言旨在用于行集而不是数组。您应该考虑更改架构。在这种情况下，junction table将是一种典型的方法。有了它，你将有三个表：

Users

UserID  UserName
------  --------
1       Putra
2       Eko
...     ...

Branches

BranchID  BranchName
--------  ----------
5         New York
6         Bandung
7         Jakarta
...       ...

UserBranches

UserID  BranchID
------  --------
1       10
2       5
1       11
...     ...

解决你的问题就像这样微不足道：

SELECT
  u.UserName,
  b.BranchName
FROM
  dbo.Users AS u
  INNER JOIN dbo.UserBranches AS ub ON u.UserID = ub.UserID
  INNER JOIN dbo.Branches AS b ON ub.BranchID = b.BranchID
;

子查询在JOIN查询上返回了多个值

2 个答案: