从 T-SQL 分隔字符串解析整数值的更好方法

Question

我有一个 SQLServer2008 R2 存储过程，其中包含用于从分隔字符串中解析出整数的算法。

下面是我为循环分隔字符串并提取分隔字符串中可能存在的任何数字而编写的 SQL 代码示例：

-- Create a delimited list for testing
DECLARE @NumericList nvarchar(MAX) = N'1, 33,44 ,55, foo ,666,77 77,8,bar,9,10'

-- Declare the delimiter
DECLARE @ListDelimiter VARCHAR(1) = ','

-- Remove white space from the list
SET @NumericList = REPLACE(@NumericList, ' ','');

-- Var that will hold the value of the delimited item during the while-loop
DECLARE @NumberInScope VARCHAR(MAX)

WHILE(LEN(@NumericList) > 0)
BEGIN
    -- Get the value to the left of the first delimiter.
    IF(CHARINDEX(@ListDelimiter, @NumericList) > 0)
        SET @NumberInScope = LEFT(@NumericList, CHARINDEX(@ListDelimiter, @NumericList))
    ELSE
        SET @NumberInScope = @NumericList   

    -- Remove the @NumberInScope value from the @NumericList
    SET @NumericList = RIGHT(@NumericList, LEN(@NumericList) - LEN(@NumberInScope))

    -- Remove the delimiter from the @NumberInScope
    SET @NumberInScope = REPLACE(@NumberInScope,@ListDelimiter,'')

    -- Print only the integer values
    IF(ISNUMERIC(@NumberInScope) = 1)
    BEGIN
        PRINT @NumberInScope
    END 
END

上面的代码工作正常，但在查看代码后，在我看来，必须有更多做同一件事的简洁方法。换句话说，是否有任何我忽略的字符串函数（或者可能是任何新的 R2 函数）可以实现，从而缩小代码并希望更易于阅读？

Answer 1

权威文章是“SQL Server 2005 中的数组和列表”以及其他”

这里显示了几种分割 CSV 的方法：CLR、数字表、WHILE 循环

Answer 2

这是代码，您还可以创建一个“split”函数并使用它

DECLARE @NumericList nvarchar(max) = N'1, 33,44 ,55, foo ,666,77 77,8,bar,9,10'

;WITH cte as (
SELECT CAST(1 as bigint) p1,  CHARINDEX(',', @NumericList+',') p2, 
CAST(null as Nvarchar(max)) NumberInScope 
UNION ALL
SELECT p2 + 1, CHARINDEX(',',@NumericList+',', p2 + 1), 
SUBSTRING(@NumericList, p1, p2-p1) 
FROM cte WHERE p2>0
)
SELECT NumberInScope from cte WHERE isnumeric(NumberInScope) > 0
OPTION (MAXRECURSION 0)

Answer 3

从 MSSql Server 2016 开始，引入了一个新关键字 STRING_SPLIT 来执行所需的操作。

SELECT STRING_SPLIT ( string , separator )

请参阅 https://msdn.microsoft.com/en-us/library/mt684588。 ASPX