Question

我正在尝试压缩存储在位掩码中的函数列表，并在枚举表中“解释”如下：

CREATE TABLE #enum([ID] [int] NOT NULL IDENTITY(1, 1) PRIMARY KEY,
                   [Display] [varchar] (50) NOT NULL,
                   [DataValue] [int] NOT NULL);

INSERT INTO [#enum] ([Display], [DataValue]) 
SELECT  'Function A', 1 
UNION SELECT 'Function B', 2 
UNION SELECT 'Function C', 4 
UNION SELECT 'Function D', 8 
UNION SELECT 'Function E', 16
UNION SELECT 'Function F', 32 
UNION SELECT 'Function G', 64;

我的数据表看起来像这样（显然很简化）：

CREATE TABLE #people ([ID] [int] NOT NULL IDENTITY(1, 1) PRIMARY KEY,
                      [PersonName] [varchar] (50) NOT NULL,
                      [Functions] [int] NOT NULL);

INSERT INTO [#people] ([PersonName], [Functions]) 
SELECT'Ken Hurt', 8 
UNION SELECT 'Justin Case', 33 
UNION SELECT 'Bill Board', 73;

现在我想在查询#people表时返回以逗号分隔的函数列表;结果如下：

ID        Name          Functions
1         Ken Hurt      Function D
2         Justin Case   Function A, Function F
3         Bill Board    Function A, Function D, Function G

我一直在关注动态SQL，PIVOT，STUFF()和FOR XML PATH()已经有一段时间了，但我显然太愚蠢了，不能消化它的美丽概念。能否请你帮忙？与WHILE甚至更糟糕的游标一起浏览列表似乎需要用大锤来破解坚果。谢谢！

Answer 1

正确的方式：

架构“已损坏”。将其标准化。

解决方法：

不需要WHILE/CURSOR/PIVOT/Dynamic-SQL。简单的按位操作将完成这项工作：

SELECT * FROM #people p CROSS APPLY(SELECT STUFF((SELECT ',' + e.Display FROM #enum e WHERE p.Functions & DataValue = DataValue ORDER BY e.DataValue FOR XML PATH('')), 1, 1, '') ) AS sub(result);

的 LiveDemo

输出：

╔════╦═════════════╦═══════════╦══════════════════════════════════╗ ║ ID ║ PersonName ║ Functions ║ result ║ ╠════╬═════════════╬═══════════╬══════════════════════════════════╣ ║ 1 ║ Bill Board ║ 73 ║ Function A,Function D,Function G ║ ║ 2 ║ Justin Case ║ 33 ║ Function A,Function F ║ ║ 3 ║ Ken Hurt ║ 8 ║ Function D ║ ╚════╩═════════════╩═══════════╩══════════════════════════════════╝

Answer 2

我解决了类似的问题：

  SELECT p.nmbCurrentLivingSituation,
    SUBSTRING(
            CASE WHEN p.nmbCurrentLivingSituation & POWER(2,0) = POWER(2,0) THEN ', Two Parent Family' ELSE '' END
          + CASE WHEN p.nmbCurrentLivingSituation & POWER(2,1) = POWER(2,1) THEN ', One Parent Family' ELSE '' END
          + CASE WHEN p.nmbCurrentLivingSituation & POWER(2,2) = POWER(2,2) THEN ', Foster' ELSE '' END
          + CASE WHEN p.nmbCurrentLivingSituation & POWER(2,3) = POWER(2,3) THEN ', Step Home' ELSE '' END
          + CASE WHEN p.nmbCurrentLivingSituation & POWER(2,4) = POWER(2,4) THEN ', Institution' ELSE '' END
          + CASE WHEN p.nmbCurrentLivingSituation & POWER(2,5) = POWER(2,5) THEN ', Living On Own' ELSE '' END
          + CASE WHEN p.nmbCurrentLivingSituation & POWER(2,6) = POWER(2,6) THEN ', Homeless' ELSE '' END
          + CASE WHEN p.nmbCurrentLivingSituation & POWER(2,7) = POWER(2,7) THEN ', Other' ELSE '' END
          + CASE WHEN p.nmbCurrentLivingSituation & POWER(2,8) = POWER(2,8) THEN ', Siblings' ELSE '' END
          + CASE WHEN p.nmbCurrentLivingSituation & POWER(2,9) = POWER(2,9) THEN ', Relatives' ELSE '' END
          + CASE WHEN p.nmbCurrentLivingSituation & POWER(2,10) = POWER(2,10) THEN ', Spouse' ELSE '' END
          + CASE WHEN p.nmbCurrentLivingSituation & POWER(2,11) = POWER(2,11) THEN ', Non-Marital Partner Childs Parent' ELSE '' END
          + CASE WHEN p.nmbCurrentLivingSituation & POWER(2,12) = POWER(2,12) THEN ', Non-Marital Partner not Childs Parent' ELSE '' END
          + CASE WHEN p.nmbCurrentLivingSituation & POWER(2,13) = POWER(2,13) THEN ', Unknown' ELSE '' END
        , 3, 150) As [values]
    FROM tblParticipant p

结果如下：

nmbCurrentLivingSituation   values
1       Two Parent Family
2       One Parent Family
NULL
0
770     One Parent Family, Siblings, Relatives

我要感谢这篇文章： In SQL, how can I split the values in a bitmask total into a comma delimited string

从枚举表中展平T-SQL位掩码

2 个答案: