How to insert a comma in between a string - sql

Question

I having a string and i need to insert a comma in between a given string. Please help me with some ideas
declare #a varchar(15) = 'asdfghj'
select #a
I expect the output as 'a,s,d,f,g,h,j'

Answer 1

This will work in sql server 2008
DECLARE #a varchar(max)='23'
DECLARE #b INT=len(#a)
WHILE #b>1
SELECT #a=stuff(#a,#b,0,','),#b-=1
SELECT #a
If you ever upgrade to sql server 2017, you can use this version, assuming the string is no longer than 2047 characters(2047 is the max number in spt_values with type=P, otherwise you can use a number table or something similar):
DECLARE #a varchar(max)='abcd'
SELECT string_agg(substring(#a,number+1,1),',')
FROM master..spt_values
WHERE number < len(#a)
and type='P'

Answer 2

SQL Server isn't designed to do this, but here's a simple way to do this in a while loop;
DECLARE #a varchar(15) = 'asdfghj'
DECLARE #i int = 1
DECLARE #output varchar(30)
WHILE (#i <= len(#a))
BEGIN
SET #output = ISNULL(#output,'') + ',' + SUBSTRING(#a, #i, 1)
SET #i = #i + 1
END
SET #output = STUFF(#output,1,1,'')
SELECT #output
Output: a,s,d,f,g,h,j
It takes each separate character of input and inserts a comma before it. The STUFF function removes the very first comma in the string, you could do this with a SUBSTRING or RIGHT if you preferred.
This would work on any length string you pass in if you tweak the length of #a and #output

Answer 3

Consider carefully Panagiotis Kanavos's comment, but if you want to do this with T-SQL, one possible approach is using recursive CTE and FOR XML (supported from SQL Server 2008):
DECLARE #a varchar(15) = 'asdfghj'
;WITH cte AS (
SELECT SUBSTRING(#a, 1, 1) AS Symbol, 1 AS Position
UNION ALL
SELECT SUBSTRING(#a, Position + 1, 1), Position + 1
FROM cte
WHERE Position < LEN(#a)
)
SELECT STUFF((
SELECT CONCAT(N',', Symbol)
FROM cte
ORDER BY Position
FOR XML PATH('')
), 1, 1, N'') AS Result
OPTION (MAXRECURSION 0)
Output:
Result
a,s,d,f,g,h,j
Notes:
Just for information, starting with SQL Server 2017 you may use STRING_AGG():
DECLARE #a varchar(15) = 'asdfghj'
;WITH cte AS (
SELECT SUBSTRING(#a, 1, 1) AS Symbol, 1 AS Position
UNION ALL
SELECT SUBSTRING(#a, Position + 1, 1), Position + 1
FROM cte
WHERE Position < LEN(#a)
)
SELECT STRING_AGG(Symbol, ',')
FROM cte
OPTION (MAXRECURSION 0)

Answer 4

As has already been mentioned, this is a terrible idea.
Do not do this in SQL Server if you can avoid it.
That said, if for some reason you can't avoid it, a set based solution to this would involve a numbers table. If you don't have one of these you can generate one with little overhead using a cte. To work with just one value you can do this:
declare #a varchar(15) = 'asdfghj';
with t(t)as(select t from(values(1),(1),(1),(1),(1),(1),(1),(1),(1),(1))as t(t))
,n(n)as(select top(len(#a)) row_number()over(order by(select null)) from t,t t2,t t3,t t4)
select #a = stuff((select ',' + substring(#a,n,1)
from n
order by n
for xml path('')
)
,1,1,''
);
select #a;
Which outputs: a,s,d,f,g,h,j
Or to apply this logic to a table of values you can do the following:
declare #t table (a varchar(100));
insert into #t values('asdfghj'),('qwerty'),('qwertyuiopasdfghjklzxcvbnm[];#?|');
with t(t)as(select t from(values(1),(1),(1),(1),(1),(1),(1),(1),(1),(1))as t(t))
,n(n)as(select top(select max(len(a)) from #t) row_number()over(order by(select null)) from t,t t2,t t3,t t4)
select stuff((select ',' + substring(a,n,1)
from n
where n.n <= len(t.a)
order by n.n
for xml path('')
)
,1,1,''
) as CommaDelimited
from #t as t;
Which outputs:
+---------------------------------------------------------------------------+
| CommaDelimited |
+---------------------------------------------------------------------------+
| a,s,d,f,g,h,j |
| q,w,e,r,t,y |
| q,w,e,r,t,y,u,i,o,p,a,s,d,f,g,h,j,k,l,z,x,c,v,b,n,m,[,],;,#,?,| |
+---------------------------------------------------------------------------+

Answer 5

Hope this works, i used the STUFF() function to insert the ,
declare #a varchar(15) = 'asdfghj'
declare #totalchar int = len(#a)
declare #counter int = #totalchar
while #counter >=1
begin
if #counter + 1 <= #totalchar
begin
set #a = stuff(#a,#counter + 1, 0 , ',')
end
set #counter = #counter -1
end
select #a

Answer 6

I agree with Panagiotis Kanavos comment strongly. Below snippet will work for you.
Declare #a varchar(15) = 'asdfghj',#OUTPUT VARCHAR(MAX)= ''
SELECT #OUTPUT = #OUTPUT+AA+',' FROM (
SELECT number ,SUBSTRING(#a, number, 1) AA
FROM master.DBO.spt_values WHERE TYPE = 'P'
AND number BETWEEN 1 AND LEN(#a)
)A
Order by number
SELECT SUBSTRING(#OUTPUT,1,LEN(#OUTPUT)-1)
I used spt_values which is undocumented by Microsoft, which is not preferred. You can try the same with Numbers table instead.

Answer 7

Try This easy method...
DECLARE #INPUT VARCHAR(10) = 'ABCD'
DECLARE #i INT = 1
DECLARE #OUTPUT VARCHAR(50) = ''
WHILE #I < = LEN(#INPUT)
BEGIN
SET #OUTPUT = #OUTPUT + SUBSTRING(#INPUT,#i,1) + ','
SET #i = #i + 1
END
SET #OUTPUT = SUBSTRING(#OUTPUT,1,LEN(#OUTPUT) - 1)
PRINT #OUTPUT