问题描述
使用SQL Server的第3天.
Day #3 with SQL Server.
我正在尝试将2列定界数据合并为一个表值函数的一个输出.这是我的数据:
I am trying to combine 2 columns of delimited data into one output from a Table Valued Function. Here is my data:
我希望以以下格式处理数据并将其放入表格中:
I would like the data to be processed and placed into a table in the following format:
我目前正在尝试使用此CROSS APPLY TSQL语句，但是我不知道自己在做什么.
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
我对CROSS APPLY的研究具有广泛的背景，我不了解在这种情况下应如何应用它.我是否需要一个带有附加CROSS APPLY的子查询和一个联接来组合两个表值函数的返回值的子查询?
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?
这是我最初使用的拆分功能(我不记得作者将其归功于这些功能):
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
修改并编辑修改后的查询
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;
推荐答案
如果我们可以看到您的分割字符串函数，则回答这个问题可能会更容易.我的答案是使用我拥有的拆分功能的版本.
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.
我将在您的拆分函数中包含一个行号，您可以使用该行号来联接拆分字符串和拆分值.
I would include in your split function a row number that you can use to JOIN the split string and the split values.
分割功能:
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;
然后，如果要拆分多个列，则可以使用类似于以下内容的查询:
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;
请参见带有演示的SQL小提琴
这使用两个子查询来生成拆分值列表，然后使用拆分函数创建的行号将它们连接起来.
This uses two subqueries that generate the list of split values, then they are joined using the row number created by the split function.
这篇关于使用CROSS APPLY的一栏以上的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！