Concatenate results in select - sql

Question

I am trying to insert values into a table that come from an other (lookup) table.
The first 3 results from the table are selected and need to be concatenated before they are inserted into an other table.
How can I alter the following insert to first concatenates them with no separation characters between the 3 names (example: JohnMaxLouise)?
INSERT INTO Table 2 VALUES ((SELECT TOP 3 names FROM Table1 ORDER BY NEWID()))
I am using SQL Server 2016 so string_agg is not available.

Answer 1

Personally, I think this is simplest with conditional aggregation:
INSERT INTO Table2
SELECT (MAX(CASE WHEN seqnum = 1 THEN name ELSE '' END) +
MAX(CASE WHEN seqnum = 2 THEN name ELSE '' END) +
MAX(CASE WHEN seqnum = 3 THEN name ELSE '' END)
)
FROM (SELECT name, ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) as seqnum
FROM (SELECT TOP 3 name
FROM Table1
ORDER BY NEWID()
) t
) t;
An alternative is an XML approach, but if you know you want three, then conditional aggregation (or pivot) works fine.

Answer 2

try the following:
declare #tab table (names varchar(max))
declare #tab1 table ([name] varchar(100))
insert into #tab1
select 'John' union select 'Max' union select 'Louise' union select 'xxx'
insert into #tab select (select top 3 [name] + '' from #tab1 for xml path(''))
select * from #tab
Thanks.

Answer 3

This will return '1,2,3,4'
DECLARE #x TABLE (i INTEGER)
DECLARE #r VARCHAR(255)
INSERT INTO #x VALUES (1),(3),(2),(4)
SELECT #r= STUFF(( SELECT ',' + CAST(i AS VARCHAR(max))
FROM #x
ORDER BY i
FOR XML PATH(''), type
).value('.','varchar(255)'), 1, 1, '')
SELECT #r

Answer 4

Solution Overview
You can use FOR XML PATH('') to achieve this, just use the following command:
SELECT '' + NAME
FROM (SELECT Top 3 NAME FROM TBL_1 ORDER BY NEWID()) AS T
FOR XML PATH('')
Or simple concatenation
SELECT #x = #x + NAME
FROM (SELECT Top 3 NAME FROM TBL_1 ORDER BY NEWID()) AS T1
Detailed Solution
SQLFiddle Demo
First i created the test environment using the following query
CREATE TABLE TBL_1 (NAME Varchar(50))
CREATE TABLE TBL_2 (NAME Varchar(50))
INSERT INTO TBL_1 (Name) VALUES ('John'),('Max'),('Louise'),('Mark'),('Peter')
Then i Used the following command
DECLARE #x varchar(255)
SELECT #x = (SELECT '' + NAME
FROM (SELECT Top 3 NAME FROM TBL_1 ORDER BY NEWID()) AS T1
FOR XML PATH('') )
INSERT INTO TBL_2(NAME) SELECT #x;
SELECT * FROM TBL_2
And the Result is JohnLouiseMax
Or you can use simple concatenation to achieve this
SQLFiddle Demo
DECLARE #x varchar(255)
SET #x = ''
SELECT #x = #x + NAME
FROM (SELECT Top 3 NAME FROM TBL_1 ORDER BY NEWID()) AS T1
INSERT INTO TBL_2(NAME) SELECT #x;
SELECT * FROM TBL_2