How to split the result row by comma - sql

Question

I have a question I have a simple table that looks like this when i do select all on it (one column with some rows)
| a, b, c | - 1st row
| b, d, d | - 2nd row
| d, e, f | - 3rd row
Now in trying to split those values by comma so each value would be in separate row something like
|a| - 1st row
|b| - 2nd row
|c| - 3rd row
|d| - 4th row
|e| - 5th row
|f| - 6th row
I was trying with something like:
select id,
case when CHARINDEX(', ', [value])>0
then SUBSTRING([value] , 1, CHARINDEX(', ',[value])-1) else [value] end firstname,
CASE WHEN CHARINDEX(', ', [value])>0
THEN SUBSTRING([value],CHARINDEX(', ',[value])+1,len([value])) ELSE NULL END as lastname from table
But it is not the way.

Answer 1

Without a UDF Parse/Split function
You didn't specify a Table or Column name so replace YourTable and YourList with your actual table and column names.
Select Distinct RetVal
,RowNr = Dense_Rank() over (Order by RetVal)
From YourTable A
Cross Apply (
Select RetSeq = Row_Number() over (Order By (Select null))
,RetVal = LTrim(RTrim(B.i.value('(./text())[1]', 'varchar(max)')))
From (Select x = Cast('<x>'+ replace((Select A.YourList as [*] For XML Path('')),',','</x><x>')+'</x>' as xml).query('.')) as A
Cross Apply x.nodes('x') AS B(i)
) B
Returns
RetVal RowNr
a 1
b 2
c 3
d 4
e 5
f 6
Using a Split/Parse function (everyone should have a good one)
Select Distinct RetVal
,RowNr = Dense_Rank() over (Order by RetVal)
From YourTable A
Cross Apply (Select * from [dbo].[udf-Str-Parse-8K](A.YourList,',') ) B
The UDF -- if interested
CREATE FUNCTION [dbo].[udf-Str-Parse-8K] (#String varchar(max),#Delimiter varchar(10))
Returns Table
As
Return (
with cte1(N) As (Select 1 From (Values(1),(1),(1),(1),(1),(1),(1),(1),(1),(1)) N(N)),
cte2(N) As (Select Top (IsNull(DataLength(#String),0)) Row_Number() over (Order By (Select NULL)) From (Select N=1 From cte1 a,cte1 b,cte1 c,cte1 d) A ),
cte3(N) As (Select 1 Union All Select t.N+DataLength(#Delimiter) From cte2 t Where Substring(#String,t.N,DataLength(#Delimiter)) = #Delimiter),
cte4(N,L) As (Select S.N,IsNull(NullIf(CharIndex(#Delimiter,#String,s.N),0)-S.N,8000) From cte3 S)
Select RetSeq = Row_Number() over (Order By A.N)
,RetVal = LTrim(RTrim(Substring(#String, A.N, A.L)))
From cte4 A
);
--Much faster than str-Parse, but limited to 8K
--Select * from [dbo].[udf-Str-Parse-8K]('Dog,Cat,House,Car',',')
--Select * from [dbo].[udf-Str-Parse-8K]('John||Cappelletti||was||here','||')

Answer 2

A recursive cte solution which finds all the ,s in the string and gets the substring between 2 ,s. (Assuming you are on a sql server version 2012+ for lead to work)
with cte as (
select val,charindex(',',','+val+',') as location from t
union all
select val,charindex(',',','+val+',',location+1) from cte
where charindex(',',','+val+',',location+1) > 0
)
,substrings as (select *,
substring(val,location,
lead(location,1) over(partition by val order by location)-location-1) as sub
from cte)
select distinct sub
from substrings
where sub is not null and sub <> ''
order by 1;
Sample Demo
1) The first cte gets all the , locations in the string recursively. , is appended at the beginning and end of the string to avoid missing the first substring before , and the last substring after ,.
2) For each string, the location of the next , is found using lead ordered by the location of ,.
3) Finally get all those substrings which are not null and are not empty strings.

Answer 3

You can do this by using cross apply and XML
select distinct
p.a.value('.','varchar(10)') col
from (
select
cast('<x>' + replace(col,', ','</x><x>') + '</x>' as XML) as x
from your_table) t
cross apply x.nodes ('/x') as p(a)
) t