SQL Server:按“/"拆分字符串并将每个拆分元素放入不同的列中 [英] SQL Server: Splitting string by '/' and put each split element into a different column

问题描述

我在外部站点上有一个表，我需要将其复制到本地数据库，但需要进行一些转换.我必须大量修改的列之一称为 product_url.URL 的格式为 site.com\category\sub-category\brand\model#.

I have a table on an external site that I need to copy to a local DB, but with some transformations. One of the columns I have to heavily modify is called product_url. The URL is in the form site.com\category\sub-category\brand\model#.

我本地数据库中的表将有 4 列来保存这些数据.它们将是类别、子类别、品牌和型号#.因此，我必须首先修剪 site.com(我使用 truncate 完成此操作)，但现在我必须解析 \category\sub-category\brand\model#

The table in my local db will have 4 columns to hold this data. They will be category, sub-category, brand and model#. So, I will have to first trim the site.com (I did this using truncate), but now I have to parse \category\sub-category\brand\model#

我从 SO 找到了一个 UDF，我认为它会有所帮助.这是:

I found a UDF from SO that I think will help out. Here it is:

create function dbo.SplitString 
    (
        @str nvarchar(4000), 
        @separator char(1)
    )
    returns table
    AS
    return (
        with tokens(p, a, b) AS (
            select 
                1, 
                1, 
                charindex(@separator, @str)
            union all
            select
                p + 1, 
                b + 1, 
                charindex(@separator, @str, b + 1)
            from tokens
            where b > 0
        )
        select
            p-1 zeroBasedOccurance,
            substring(
                @str, 
                a, 
                case when b > 0 then b-a ELSE 4000 end) 
            AS s
        from tokens
      )
    GO

现在我在使用此功能时遇到问题.可能是因为我缺乏 UDF 的经验.

Now I am having trouble using this function. Probably due to my lack of experience with UDF's.

这是我现在所拥有的:

select s from
dbo.SplitString(select substring(product_url, 8, len(product_url)) 
            from Products, '/')
where zeroBasedOccurance=0 AS Category

这显然在语法上也不正确.

This is obviously not even syntactically correct.

我想知道我是否以最好的方式解决这个问题.我还不是一个 DBA，所以我很难解决这个问题.我只需要弄清楚如何为 product_url 表中的每一行应用这个 UDF ~4 次.

I am wondering if I am going about this the best way. I am not yet much of a DBA, so I am having a hard time wrapping my head around this issue. I just need to figure out how to apply this UDF ~4 times for each row in the product_url table.

推荐答案

不确定你的功能，但这是我的:

Not sure about your function, but here is mine:

CREATE FUNCTION dbo.FN_PARSENAME(@chunk VARCHAR(4000), @delimiter CHAR(1), @index INT )
RETURNS VARCHAR(1000)
AS
BEGIN
DECLARE
    @curIndex INT = 0,
    @pos INT = 1,
    @prevPos INT = 0,
    @result VARCHAR(1000)

WHILE @pos > 0
BEGIN

    SET @pos =  CHARINDEX(@delimiter, @chunk, @prevPos);

    IF(@pos > 0)
    BEGIN -- Characters between position and previous position
        SET @result = SUBSTRING(@chunk, @prevPos, @pos-@prevPos)
    END
    ELSE
    BEGIN -- Last Delim
        SET @result = SUBSTRING(@chunk, @prevPos, LEN(@chunk))
    END

    IF(@index = @curIndex)
    BEGIN
        RETURN @result
    END

    SET @prevPos = @pos + 1
    SET @curIndex = @curIndex + 1;
END
RETURN '' -- Else Empty
END

你这样称呼它:
SELECT Address_Line1 = dbo.fn_Parsename(Merged,'|', 0)从表

其中Merged是被分隔的字段，'|'是分隔符，因此您可以将其设为\"，0 是您想要的字符串部分，0 是第一个，向上.

Wherein Merged is the field that is delimited, the '|' is the delimiter, so you would make it '\', and the 0 is which portion of the string you want, 0 being the first, on up.

对于您的示例，它将是:

For your example it would be:

SELECT category = dbo.fn_Parsename(product_url,'\', 1)
     , sub-category = dbo.fn_Parsename(product_url,'\', 2)
     , brand = dbo.fn_Parsename(product_url,'\', 3)
     , model# = dbo.fn_Parsename(product_url,'\', 4)
FROM Table 

或者可能是 0-3 取决于.

Or maybe 0-3 depending.

我非常有信心根据我发现的东西改编它，甚至可能是在 SO 上，但我不记得谁应该受到赞扬.

I'm pretty confident I adapted that from something I found, perhaps even on SO, but I can't recall who would deserve credit.

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