SQL拆分函数 [英] SQL Split function

问题描述

我正在寻找一种方法来做到这一点......

I'm looking for a way to do this ...

SELECT FirstName, LastName, Split(AddressBlock, '  ', 1), Split(AddressBlock, ' ', 2), PostCode 
FROM Contacts

我想传递的参数是...

The arguments I want to pass are ...

1. 地址
2. 分隔符(当前情况需要 2 个空格，但这可能是一个逗号或一个空格后跟一个逗号)或其他内容(它会有所不同).
3. 我想返回的地址部分(我并不总是需要拆分结果的所有部分).

我似乎能够在互联网上找到一些拆分函数的示例，但它们返回一个包含整个拆分部分集的表.

I seem to be able to find a few examples of splitting functions about the internet but they return a table containing the entire set of split parts.

我的 SQL 技能不是很好，所以我需要非常简单的答案.我一直在处理 nvarchar 数据，并且该函数需要可重用.

My SQL skills aren't that great so I need the answer to be ultra simple. I'm always working with nvarchar data and the function needs to be reusable.

推荐答案

如果您想要一个用户定义的函数来执行此操作，这应该可行.不是很漂亮，但是...

If you want a user-defined function to do this, this should work. Not that pretty, but...

CREATE FUNCTION dbo.SplitStringPart (
    @input nvarchar(MAX),
    @separator nvarchar(10),
    @index int
) RETURNS nvarchar(MAX)
BEGIN

DECLARE @counter int,
        @position int,
        @oldposition int,
        @separatorlength int,
        @result nvarchar(MAX)

SET @separatorlength = DATALENGTH(@separator) / 2
IF @separatorlength = 0 RETURN NULL

SET @result = NULL

SET @counter = 1
SET @position = -2

WHILE (@counter <= @index)
BEGIN

    SET @oldposition = @position
    SET @position = CHARINDEX(@separator, @input, @position + 1)
    IF @position = 0 AND @counter < @index
    BEGIN
        SET @oldposition = 0
        BREAK
    END
    SET @counter = @counter + 1

END

IF @oldposition = 0 AND @position = 0
    RETURN NULL
ELSE IF @oldposition < 0
BEGIN
    IF @position = 0 AND @index = 1
        SET @result = @input
    ELSE
        SET @result = SUBSTRING(@input, 0, @position)
END
ELSE IF @position <= 0
    SET @result = SUBSTRING(@input, @oldposition + @separatorlength, LEN(@input) - @oldposition - @separatorlength)
ELSE
    SET @result = SUBSTRING(@input, @oldposition + @separatorlength, @position - @oldposition - @separatorlength)

RETURN @result

END
GO

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