在SQL中将字符串拆分为多列

Question

我有下表：

 Code |           Column
 -----+-----------------------------
 152  |    12_25_62_26_65_22_88
 247  |    55_56_85_52_11_45_63
 369  |    45_65_25_89_52_54_96

如何编写获得此类结果的SELECT查询？：

 Code | Col1 | Col2 | Col3 | Col4 | Col5 | Col6 | Col7
 -----+------+------+------+------+------+------+-------
 152  |  12  |  25  |  62  |  26  |  65  |  22  |  88
 247  |  55  |  56  |  85  |  52  |  11  |  45  |  63
 369  |  45  |  65  |  25  |  89  |  52  |  54  |  96

Answer 1

我这样说吧：

DECLARE @mockup TABLE (Code INT, [Column] VARCHAR(100));
INSERT INTO @mockup VALUES
(152 , '12_25_62_26_65_22_88'),
(247 , '55_56_85_52_11_45_63'),
(369 , '45_65_25_89_52_54_96');

WITH Splitted AS
(
    SELECT Code
          ,[Column] 
          ,CAST('<x>' + REPLACE([Column],'_','</x><x>') + '</x>' AS XML) AS Parts 
    FROM @mockup
)
SELECT Code,[Column]
      ,Parts.value(N'/x[1]','int') AS Col1
      ,Parts.value(N'/x[2]','int') AS Col2
      ,Parts.value(N'/x[3]','int') AS Col3
      ,Parts.value(N'/x[4]','int') AS Col4
      ,Parts.value(N'/x[5]','int') AS Col5
      ,Parts.value(N'/x[6]','int') AS Col6
      ,Parts.value(N'/x[7]','int') AS Col7
FROM Splitted;

通过XML分割字符串的技巧允许直接使用其位置来处理每个元素。如果字符串包含各种类型（在您的情况下，所有值都是int），这尤其有用。你可以很容易地检索所有类型安全的类型。

注意这是一个糟糕的设计。如果你可以改变这个，你应该避免在一列中存储多个值..，

Answer 2

你可以用它。

DECLARE @MyTable TABLE (Code INT, [Column] VARCHAR(100))
 INSERT INTO @MyTable VALUES
 (152 , '12_25_62_26_65_22_88'),
 (247 , '55_56_85_52_11_45_63'),
 (369 , '45_65_25_89_52_54_96')



SELECT Code, [1] Col1, [2] Col2, [3] Col3, [4] Col4, [5] Col5, [6] Col6, [7] Col7 FROM (
    select Code, Rn, Col from ( 
        select Code, CAST('<Root><row>' + REPLACE([Column],'_','</row><row>') + '</row></Root>'  as XML) [ColumnXml] from @MyTable
    ) T
    outer apply (select ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) RN, T.c.value( '.', 'integer') from T.[ColumnXml].nodes('/Root/row') T(c) ) ColTable(Rn, Col)
) SRC PIVOT( MAX(Col) FOR RN IN ([1],[2],[3],[4],[5],[6],[7])) PVT

结果：

Code        Col1        Col2        Col3        Col4        Col5        Col6        Col7
----------- ----------- ----------- ----------- ----------- ----------- ----------- -----------
152         12          25          62          26          65          22          88
247         55          56          85          52          11          45          63
369         45          65          25          89          52          54          96

Answer 3

您可以使用动态SQL来实现此目的：

DECLARE @MyTable TABLE (Code INT, [Column] VARCHAR(100))
INSERT INTO @MyTable VALUES
(152 , '12_25_62_26_65_22_88'),
(247 , '55_56_85_52_11_45_63'),
(369 , '45_65_25_89_52_54_96')

declare @query nvarchar(1000)
set @query = ''
select @query = @query + 'select ' + cast(code as nchar(3)) + ',' + replace([column],'_',',') + ' union all ' from @MyTable
--remove last ten characters (union all statement)
set @query = left( @query, len(@query) - 10)
execute sp_executesql @query