How can I split a single column value containing multiple values into multiple columns in SQL Server?-Mysql Tutorial-php.cn

How can I split a single column value containing multiple values into multiple columns in SQL Server?

Susan Sarandon

Release： 2024-12-23 19:13:09

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How can I split a single column value containing multiple values into multiple columns in SQL Server?

Splitting a Single Column Value into Multiple Columns

The task of splitting a single column containing multiple values into separate columns can arise in data management. For instance, consider a table with a column named "SubscriptionNumber" that stores subscription details in a single field. To make the data more manageable and accessible, we need to extract the individual values into multiple columns.

Approach Using Cross Apply and XML

One method to achieve this is by using a cross apply and XML manipulation technique. Let's assume we have a table called "Subscriptions" with a column "SubscriptionNumber". The sample data in this column is as follows:

SC 5-1395-174-25P 
SC 1-2134-123-ABC C1-2
SC 12-5245-1247-14&amp;P
SC ABCD-2525-120

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To split these values into separate columns, we can employ the following query:

Declare @YourTable table (SubscriptionNumber varchar(max))
Insert Into @YourTable values
('SC 5-1395-174-25P'),
('SC 1-2134-123-ABC C1-2'),
('SC 12-5245-1247-14&amp;P'),
('SC ABCD-2525-120')

Select B.*
 From  @YourTable A
 Cross Apply (
                Select Pos1 = ltrim(rtrim(xDim.value('/x[1]','varchar(max)')))
                      ,Pos2 = ltrim(rtrim(xDim.value('/x[2]','varchar(max)')))
                      ,Pos3 = ltrim(rtrim(xDim.value('/x[3]','varchar(max)')))
                      ,Pos4 = ltrim(rtrim(xDim.value('/x[4]','varchar(max)')))
                      ,Pos5 = ltrim(rtrim(xDim.value('/x[5]','varchar(max)')))
                      ,Pos6 = ltrim(rtrim(xDim.value('/x[6]','varchar(max)')))
                      ,Pos7 = ltrim(rtrim(xDim.value('/x[7]','varchar(max)')))
                From  (Select Cast('<x>' + replace((Select replace(replace(A.SubscriptionNumber,' ','-'),'-','§§Split§§') as [*] For XML Path('')),'§§Split§§','</x><x>')+'</x>' as xml) as xDim) as A 
             ) B

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This query uses a cross apply to generate a set of rows for each row in the @YourTable table. Within the cross apply, the XML datatype is employed to convert the SubscriptionNumber value into an XML fragment. The XML fragment is then parsed to extract the individual values and assign them to the columns Pos1 to Pos7.

Alternative Approach Using Dynamic SQL

A dynamic SQL approach can also be used to split the SubscriptionNumber column into multiple columns. This approach requires the creation of a temporary table to store the split values:

Declare @YourTable table (SubscriptionNumber varchar(max))
Insert Into @YourTable values
('SC 5-1395-174-25P'),
('SC 1-2134-123-ABC C1-2'),
('SC 12-5245-1247-14&amp;P'),
('SC ABCD-2525-120')

Declare @ColNames nvarchar(max) = ''
Declare @SQL nvarchar(max) = 'CREATE TABLE #TempTable (SubscriptionNumber varchar(max), '

-- Generate column names dynamically
Select @ColNames += ', Col' + CAST(Row_Number() OVER (ORDER BY (SELECT NULL)) AS nvarchar(10))
From (Select * From @YourTable) AS T
Cross Join (Select * From @YourTable) AS T2

-- Append column names to SQL statement
Set @SQL += @ColNames + ')'

-- Execute the dynamic SQL to create the temporary table
Exec (@SQL)

-- Insert split values into the temporary table
Insert Into #TempTable
Select SubscriptionNumber,
       ltrim(rtrim(xDim.value('/x[1]','varchar(max)')))
     , ltrim(rtrim(xDim.value('/x[2]','varchar(max)')))
     , ltrim(rtrim(xDim.value('/x[3]','varchar(max)')))
     , ltrim(rtrim(xDim.value('/x[4]','varchar(max)')))
     , ltrim(rtrim(xDim.value('/x[5]','varchar(max)')))
     , ltrim(rtrim(xDim.value('/x[6]','varchar(max)')))
     , ltrim(rtrim(xDim.value('/x[7]','varchar(max)')))
From @YourTable
Cross Apply (
                Select Cast('<x>' + replace((Select replace(replace(SubscriptionNumber,' ','-'),'-','§§Split§§') as [*] For XML Path('')),'§§Split§§','</x><x>')+'</x>' as xml) as xDim) as A 

-- Select data from the temporary table
Select * From #TempTable

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The dynamic SQL approach dynamically generates the SQL statement to create a temporary table with the appropriate column names. The split values are then inserted into this temporary table, and the data can be selected from the temporary table as required.

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