T-SQL: split and aggregate comma-separated values - sql-server-2008

Question

I have the following table with each row having comma-separated values:
ID
-----------------------------------------------------------------------------
10031,10042
10064,10023,10060,10065,10003,10011,10009,10012,10027,10004,10037,10039
10009
20011,10027,10032,10063,10023,10033,20060,10012,10020,10031,10011,20036,10041
I need to get a count for each ID (a groupby).
I am just trying to avoid cursor implementation and stumped on how to do this without cursors.
Any Help would be appreciated !

Answer 1

You will want to use a split function:
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)<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) values(#slice)
set #String = right(#String,len(#String) - #idx)
if len(#String) = 0 break
end
return
end;
And then you can query the data in the following manner:
select items, count(items)
from table1 t1
cross apply dbo.split(t1.id, ',')
group by items
See SQL Fiddle With Demo

Answer 2

Well, the solution i always use, and probably there might be a better way, is to use a function that will split everything. No use for cursors, just a while loop.
if OBJECT_ID('splitValueByDelimiter') is not null
begin
drop function splitValueByDelimiter
end
go
create function splitValueByDelimiter (
#inputValue varchar(max)
, #delimiter varchar(1)
)
returns #results table (value varchar(max))
as
begin
declare #delimeterIndex int
, #tempValue varchar(max)
set #delimeterIndex = 1
while #delimeterIndex > 0 and len(isnull(#inputValue, '')) > 0
begin
set #delimeterIndex = charindex(#delimiter, #inputValue)
if #delimeterIndex > 0
set #tempValue = left(#inputValue, #delimeterIndex - 1)
else
set #tempValue = #inputValue
if(len(#tempValue)>0)
begin
insert
into #results
select #tempValue
end
set #inputValue = right(#inputValue, len(#inputValue) - #delimeterIndex)
end
return
end
After that you can call the output like this :
if object_id('test') is not null
begin
drop table test
end
go
create table test (
Id varchar(max)
)
insert
into test
select '10031,10042'
union all select '10064,10023,10060,10065,10003,10011,10009,10012,10027,10004,10037,10039'
union all select '10009'
union all select '20011,10027,10032,10063,10023,10033,20060,10012,10020,10031,10011,20036,10041'
select value
from test
cross apply splitValueByDelimiter(Id, ',')
Hope it helps, although i am still looping through everything

Answer 3

After reiterating the comment above about NOT putting multiple values into a single column (Use a separate child table with one value per row!),
Nevertheless, one possible approach: use a UDF to convert delimited string to a table. Once all the values have been converted to tables, combine all the tables into one table and do a group By on that table.
Create Function dbo.ParseTextString (#S Text, #delim VarChar(5))
Returns #tOut Table
(ValNum Integer Identity Primary Key,
sVal VarChar(8000))
As
Begin
Declare #dlLen TinyInt -- Length of delimiter
Declare #wind VarChar(8000) -- Will Contain Window into text string
Declare #winLen Integer -- Length of Window
Declare #isLastWin TinyInt -- Boolean to indicate processing Last Window
Declare #wPos Integer -- Start Position of Window within Text String
Declare #roVal VarChar(8000)-- String Data to insert into output Table
Declare #BtchSiz Integer -- Maximum Size of Window
Set #BtchSiz = 7900 -- (Reset to smaller values to test routine)
Declare #dlPos Integer -- Position within Window of next Delimiter
Declare #Strt Integer -- Start Position of each data value within Window
-- -------------------------------------------------------------------------
-- ---------------------------
If #delim is Null Set #delim = '|'
If DataLength(#S) = 0 Or
Substring(#S, 1, #BtchSiz) = #delim Return
-- --------------------------------------------
Select #dlLen = DataLength(#delim),
#Strt = 1, #wPos = 1,
#wind = Substring(#S, 1, #BtchSiz)
Select #winLen = DataLength(#wind),
#isLastWin = Case When DataLength(#wind) = #BtchSiz
Then 0 Else 1 End,
#dlPos = CharIndex(#delim, #wind, #Strt)
-- --------------------------------------------
While #Strt <= #winLen
Begin
If #dlPos = 0 Begin -- No More delimiters in window
If #isLastWin = 1 Set #dlPos = #winLen + 1
Else Begin
Set #wPos = #wPos + #Strt - 1
Set #wind = Substring(#S, #wPos, #BtchSiz)
-- ----------------------------------------
Select #winLen = DataLength(#wind), #Strt = 1,
#isLastWin = Case When DataLength(#wind) = #BtchSiz
Then 0 Else 1 End,
#dlPos = CharIndex(#delim, #wind, 1)
If #dlPos = 0 Set #dlPos = #winLen + 1
End
End
-- -------------------------------
Insert #tOut (sVal)
Select LTrim(Substring(#wind,
#Strt, #dlPos - #Strt))
-- -------------------------------
-- Move #Strt to char after last delimiter
Set #Strt = #dlPos + #dlLen
Set #dlPos = CharIndex(#delim, #wind, #Strt)
End
Return
End
Then write, (using your table schema),
Declare #AllVals VarChar(8000)
Select #AllVals = Coalesce(#allVals + ',', '') + ID
From Table Where ID Is Not null
-- -----------------------------------------
Select sVal, Count(*)
From dbo.ParseTextString(#AllVals, ',')
Group By sval