Sql Server - Is there any way to `Concat` nvarchar column in Select Such as `Agregate functions` - sql

Question

Hi I Have Table that called Tags, in tag table I have 2 columns (QuestionID int ,Tag nvachar(100))
I want to Select Questions with all Tags in one column like the below
QuestionID Tag
---------- ----
1 Math
1 Integral
2 Physics
QuestionID QuestionText
---------- -----------
1 What is 2*2?
2 What is Quantom roles?
QuestionID QuestionText Tags
---------- ----------- -------
1 What is 2*2? Math, Integral
2 What is Quantom roles? Physics
Can any one help me with out using scalar value function

Answer 1

There are two ways to answer this:
can use a query like in other answer, but this is work for one table only.
create clr aggregate function for this like a below code (my code in C#).
this solution work for all tables and simple for use,
only use: select Concat(column) from Table in sql server
using System;
using System.Data;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using Microsoft.SqlServer.Server;
using System.Text;
[Serializable]
[Microsoft.SqlServer.Server.SqlUserDefinedAggregate(Format.UserDefined, IsInvariantToDuplicates = false, IsInvariantToNulls = true, IsInvariantToOrder = false, IsNullIfEmpty = true, MaxByteSize = -1)]
public struct Concat : IBinarySerialize
{
public void Init()
{
SB = new StringBuilder();
}
public void Accumulate(SqlString Value)
{
if (Value.IsNull)
return;
if (SB.Length > 0)
SB.Append("\n");
SB.Append(Value);
}
public void Merge(Concat Group)
{
if (SB.Length > 0 && Group.SB.Length > 0)
SB.Append("\n");
SB.Append(Group.SB.ToString());
}
public SqlString Terminate()
{
return new SqlString(SB.ToString());
}
// This is a place-holder member field
StringBuilder SB;
public void Read(System.IO.BinaryReader r)
{
SB = new StringBuilder(r.ReadString());
}
public void Write(System.IO.BinaryWriter w)
{
w.Write(SB.ToString());
}
}

Answer 2

CREATE TABLE #temp
(
QuestionID INT,
Tag NVARCHAR(100)
)
INSERT INTO #temp
(QuestionID,Tag)
VALUES (1,N'Math'),
(1,N'Integral'),
(2,N'Physics')
CREATE TABLE #temp1
(
QuestionID INT,
QuestionText NVARCHAR(100)
)
INSERT INTO #temp1
(QuestionID,QuestionText)
VALUES (1,N'What is 2*2?'),
(2,'What is Quantom roles?')
SELECT h.QuestionID,
h.QuestionText,
Stuff((SELECT ', ' + CONVERT(VARCHAR, b.TAG)
FROM #temp b
WHERE b.QuestionID = h.QuestionID
FOR XML PATH('')), 1, 2, '')
FROM #temp t
JOIN #temp1 h
ON t.QuestionID = h.QuestionID
GROUP BY h.QuestionID,
h.QuestionText

Answer 3

SELECT q.QuestionText
,STUFF((
SELECT ', ' + t2.Tag
FROM Tags t2
WHERE t1.QuestionID = t2.QuestionID
ORDER BY t2.Tag
FOR XML PATH('')
,TYPE
).value('.', 'varchar(max)'), 1, 2, '') AS Tag
FROM Questions q
INNER JOIN Tags t1
ON q.QuestionID = t1.QuestionID
GROUP BY q.QuestionText
,t1.QuestionID
Working example : http://sqlfiddle.com/#!3/e8f0f/7

Answer 4

Try this
create function fn_comma (#question_id int)
returns varchar(100)
as
begin
declare #value varchar(100)
set #value=(SELECT top 1 STUFF((SELECT ', ' + CAST(Value AS VARCHAR(10)) [text()]
FROM Tags
WHERE ID = t.ID
FOR XML PATH(''), TYPE)
.value('.','NVARCHAR(MAX)'),1,2,' ') List_Output
FROM Tags
--where id=1
GROUP BY ID)
return #value
end

Answer 5

Try sub query to concat column data in comma separated values like below :
SELECT [QuestionID],
[QuestionText],
STUFF(( SELECT ',' + [Tag]
FROM [dbo].[Tags]
WHERE [QuestionID] = [Question].[QuestionID]
FOR XML PATH ('')), 1, 1, '') AS [Tags]
FROM [dbo].[Question]
SQL Fiddle Demo

Answer 6

Try the below idea. You just need to rewrite it as a function, then it will return all tags for the question id:
declare #function_in_questionid_para as #int
with std as
(select *,ROW_NUMBER() over(partition by QuestionID order by QuestionID,tag) as dd from #temp)
select * #temp3 into from std
declare #counter as int
set #counter = (select count(*) from #temp where QuestionID = #function_in_questionid_para as #int)
declare #c as int = 1
declare #tags as varchar(200) = ''
while (#c <= #counter)
begin
if (#c > 1) set #tags = #tags + ', '
set #tags = #tags + (select tag from #temp3 where QuestionID = #function_in_questionid_para as #int and dd = #c)
set #c = #c + 1
end
print #tags