从枚举 table 中展平 T-SQL 位掩码

Question

我正在尝试展平存储在位掩码中的函数列表，这些函数在枚举 table 中 "explained" 如下所示：

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 table 看起来像这样（显然简化了很多）：

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 return 在查询 #people table 时使用逗号分隔的函数列表；结果是这样的：

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

我已经关注 Dynamic SQL、PIVOT、STUFF() 和 FOR XML PATH() 有一段时间了，但我显然太笨了，无法消化美丽的概念。能否请你帮忙？使用 WHILE 或更糟的 Cursors 浏览列表就像用大锤敲碎坚果一样。谢谢！

Answer 1

正确方法：

架构是 "broken"。归一化。

解决方法：

不需要WHILE/CURSOR/PIVOT/Dynamic-SQL。简单的按位运算就可以完成工作：

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);

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

我这样解决了我非常相似的问题：

  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

结果如下所示：

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

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

从枚举 table 中展平 T-SQL 位掩码

Flattening T-SQL bitmask from enumeration table

sql

tsql

sql-server

pivot