How to Transform Comma-Separated Column Data into Distinct Rows in SQL?

Extracting Row Data from Split Column Data in SQL

To split column data into distinct rows, you can leverage a custom function and apply it to your existing table using an outer join. This enables you to transform data like this:

Code  Declaration
123   a1-2 nos, a2- 230 nos, a3 - 5nos

Into the desired format:

Code  Declaration 
123   a1 - 2nos 
123   a2 - 230nos 
123   a3 - 5nos

Using a Split Function

Create a split function called [dbo].[Split] to separate the data using a ',' delimiter:

create FUNCTION [dbo].[Split](@String varchar(MAX), @Delimiter char(1))       
returns @temptable TABLE (items varchar(MAX))       
as       
begin      
    declare @idx int       
    declare @slice varchar(8000)       

    select @idx = 1       
        if len(@String)0)  
            insert into @temptable(Items) values(@slice)       

        set @String = right(@String,len(@String) - @idx)       
        if len(@String) = 0 break       
    end   
return 
end;

Applying the Split Function

Use the split function in a query to join the new table to the original:

select t1.code, s.items declaration
from yourtable t1
outer apply dbo.split(t1.declaration, ',') s

This will produce the desired output.

Using a CTE

Alternatively, you can implement a CTE (Common Table Expression) version:

;with cte (code, DeclarationItem, Declaration) as
(
  select Code,
    cast(left(Declaration, charindex(',',Declaration+',')-1) as varchar(50)) DeclarationItem,
         stuff(Declaration, 1, charindex(',',Declaration+','), '') Declaration
  from yourtable
  union all
  select code,
    cast(left(Declaration, charindex(',',Declaration+',')-1) as varchar(50)) DeclarationItem,
    stuff(Declaration, 1, charindex(',',Declaration+','), '') Declaration
  from cte
  where Declaration > ''
) 
select code, DeclarationItem
from cte

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