Using CROSS APPLY for more than one column

问题

Day #3 with SQL Server.

I am trying to combine 2 columns of delimited data into one output from a Table Valued Function. Here is my data:

I would like the data to be processed and placed into a table in the following format:

I am currently trying to use this CROSS APPLY TSQL statement, but I don't know what I'm doing.

USE [Metrics]
INSERT INTO dbo.tblSplitData(SplitKey, SplitString, SplitValues)
SELECT d.RawKey, c.*, e.*
FROM dbo.tblRawData d
CROSS APPLY dbo.splitstringcomma(d.DelimitedString) c, dbo.splitstringcomma(d.DelimitedValues) e

My research on CROSS APPLY has broad context, and I don't understand how it should be applied in this scenario. Do I need a subquery with an additional CROSS APPLY and a join to combine the returns from the two Table Valued Functions?

Here is the split function I was using originally (I can't remember the author to credit them):

CREATE FUNCTION [dbo].[splitstring] ( @stringToSplit VARCHAR(MAX), @Delimiter CHAR(1))
RETURNS
 @returnList TABLE ([Name] [nvarchar] (500))
AS
BEGIN

 DECLARE @name NVARCHAR(255)
 DECLARE @pos INT

 WHILE CHARINDEX(@Delimiter, @stringToSplit) > 0
 BEGIN
  SELECT @pos  = CHARINDEX(@Delimiter, @stringToSplit)  
  SELECT @name = SUBSTRING(@stringToSplit, 1, @pos-1)

  INSERT INTO @returnList 
  SELECT @name

  SELECT @stringToSplit = SUBSTRING(@stringToSplit, @pos+1, LEN(@stringToSplit)-@pos)
 END

 INSERT INTO @returnList
 SELECT @stringToSplit

 RETURN
END

Edit & Revised Query

USE [Metrics] 
INSERT INTO dbo.tblSplitData(SplitKey, SplitString, SplitValues)
SELECT s.RawKey, s.SplitString, v.SplitValues
FROM (
SELECT d.RawKey, d.DelimitedString,
 c.item SplitString, c.rn
FROM dbo.tblRawData d
CROSS APPLY dbo.splitstring(d.DelimitedString, ',') c
) s

INNER JOIN

(
SELECT d.RawKey, d.DelimitedValues,
 c.item SplitValues, c.rn
FROM dbo.tblRawData d
CROSS APPLY dbo.splitstring(d.DelimitedValues, ',') c
) v
on s.RawKey = v.RawKey
and s.rn = v.rn;

回答1:

It might be easier to answer this if we could see your split string function. My answer is using a version of my split function that I have.

I would include in your split function a row number that you can use to JOIN the split string and the split values.

Split function:

CREATE FUNCTION [dbo].[Split](@String varchar(MAX), @Delimiter char(1))       
returns @temptable TABLE (items varchar(MAX), rn int)       
as       
begin      
    declare @idx int       
    declare @slice varchar(8000)   
    declare @rn int = 1 -- row number that increments with each value in the delimited string

    select @idx = 1       
        if len(@String)<1 or @String is null  return       

    while @idx!= 0       
    begin       
        set @idx = charindex(@Delimiter,@String)       
        if @idx!=0       
            set @slice = left(@String,@idx - 1)   
        else       
            set @slice = @String       

        if(len(@slice)>0)  
            insert into @temptable(Items, rn) values(@slice, @rn)       

        set @String = right(@String,len(@String) - @idx)       
        set @rn = @rn +1

        if len(@String) = 0 break       
    end   
return 
end;

Then if you have multiple columns to split, you could use a query similar to the following:

INSERT INTO dbo.tblSplitData(SplitKey, SplitString, SplitValues)
select s.rawkey,
  s.splitstring,
  v.splitvalues
from
(
  SELECT d.RawKey, d.delimitedstring, d.delimitedvalues, 
    c.items SplitString, 
    c.rn
  FROM dbo.tblRawData d
  CROSS APPLY dbo.Split(d.DelimitedString, ',') c
) s
inner join
(
  SELECT d.RawKey, d.delimitedstring, d.delimitedvalues, 
    c.items SplitValues, 
    c.rn
  FROM dbo.tblRawData d
  CROSS APPLY dbo.Split(d.DelimitedValues, ',') c
) v
  on s.rawkey = v.rawkey
  and s.delimitedstring = v.delimitedstring
  and s.rn = v.rn;

See SQL Fiddle with Demo

This uses two subqueries that generate the list of split values, then they are joined using the row number created by the split function.

回答2:

Since you are on Sql Server 2008 .You can do this without a UDF using XML.

;WITH CTE1 AS
( 
    SELECT *
    ,RN= Row_Number() OVER( Partition BY DelemitedString,DelimitedValues,RawKey,TableID ORDER BY TableID)
     FROM 
    (
    SELECT *
    ,DelimitedStringXML = CAST('<d>'+REPLACE(DelemitedString,',','</d><d>')+'</d>' AS XML)
    ,DelimitedValueXML = CAST('<d>'+REPLACE(DelimitedValues,',','</d><d>')+'</d>' AS XML)

     FROM dbo.tblRawData
    ) as t
    Cross Apply
    (
    SELECT y.value('.', 'VARCHAR(30)') AS SplitString FROM DelimitedStringXML.nodes('//d') as  x(y)

    ) as b
)
,CTE2 AS 
(
    SELECT *
    ,RN= Row_Number() OVER( Partition BY DelemitedString,DelimitedValues,RawKey,TableID ORDER BY TableID)
     FROM 
    (
    SELECT *
    ,DelimitedStringXML = CAST('<d>'+REPLACE(DelemitedString,',','</d><d>')+'</d>' AS XML)
    ,DelimitedValueXML = CAST('<d>'+REPLACE(DelimitedValues,',','</d><d>')+'</d>' AS XML)

     FROM dbo.tblRawData
    ) as t
    CROSS APPLY
    (
    SELECT h.value('.', 'VARCHAR(30)') AS SplitValue FROM DelimitedValueXML.nodes('//d') as  g(h)

    ) as c
)


SELECT a.RawKey,a.SplitString,b.SplitValue 
FROM CTE1 as a
INNER JOIN CTE2 as b
    on  a.TableID= b.TableID
    AND a.RN = b.RN

Here is SQLFiddle Demo

来源：https://stackoverflow.com/questions/16362318/using-cross-apply-for-more-than-one-column

标签

sql-server-2008

tsql

ssms

delimited-text

cross-apply