Question

my goal is if I have this:

colmuns      c1 | c2 | c3 | c4 | c5 | n..
row1          a |  a |  a |  a |  a | 
row2          b |  b |  b |  b |  b |
rowN...

I want to do a query that would return

   myCol
   aaaaa
   bbbbb
   nnnnn...

I know I can do this

select t2.id, (
    select  *
    from mytable t1
    where t1.id= t2.id
    for xml path('')) as row
from mytable t2

and it will put the whole row with many columns into one column like I want

now, how to filter out the xml tag?

or is there any other solution?

edit
column might be null are not varchar, could be int, varchar, date, etc

Answer 1

try:

;with XmlValues  as
(
    select t2.id, (
        select  *
        from mytable  t1
        where t1.id= t2.id
        for xml path(''), TYPE) as row
    from mytable  t2
)
select x.row.value('.', 'VARCHAR(8000)') as readable
    FROM XmlValues AS x

EDIT working sample:

DECLARE @YourTable table (c1 int, c2 int, c3 varchar(5), c4 datetime)
INSERT INTO @YourTable VALUES (1,2,'abcde','1/1/2009')
INSERT INTO @YourTable VALUES (100,200,'zzz','12/31/2009 23:59:59')

    select t2.c1, (
        select  *
        from @YourTable  t1
        where t1.c1= t2.c1
        for xml path(''), TYPE) as row
    from @YourTable  t2

;with XmlValues  as
(
    select t2.c1, (
        select  *
        from @YourTable  t1
        where t1.c1= t2.c1
        for xml path(''), TYPE) as row
    from @YourTable  t2
)
select x.c1,x.row.value('.', 'VARCHAR(8000)') as readable
    FROM XmlValues AS x

OUTPUT:

c1          row
----------- --------------------------------------------------------------------
1           <c1>1</c1><c2>2</c2><c3>abcde</c3><c4>2009-01-01T00:00:00</c4>
100         <c1>100</c1><c2>200</c2><c3>zzz</c3><c4>2009-12-31T23:59:59</c4>

(2 row(s) affected)

c1          readable
----------- ----------------------------------
1           12abcde2009-01-01T00:00:00
100         100200zzz2009-12-31T23:59:59

(2 row(s) affected)

EDIT loop free way to parse table column names from meta data tables, with the ability to format each datatype as desired and supports NULLs:

BEGIN TRY 
CREATE TABLE YourTable (c1 int, c2 int, c3 varchar(5), c4 datetime) 
INSERT INTO YourTable VALUES (1,2,'abcde','1/1/2009')
INSERT INTO YourTable VALUES (100,200,'zzz','12/31/2009 23:59:59')
end try begin catch end catch

DECLARE @YourTableName   varchar(1000)
DECLARE @YourColumns     varchar(max)
DECLARE @YourQuery       varchar(max)
SET @YourTableName='YourTable'
SELECT
    @YourColumns=STUFF(
                       (SELECT
                            '+ '
                            --' ' --any constant string to appear between columns
                            + CASE DATA_TYPE
                                  WHEN 'datetime' THEN 'COALESCE(CONVERT(char(23),'+CONVERT(varchar(max),COLUMN_NAME)+',121),''NULL'')'
                                  --more datatypes here
                                  ELSE 'COALESCE(CONVERT(varchar(max),' + CONVERT(varchar(max),COLUMN_NAME)+'),''NULL'')'
                              END
                            FROM INFORMATION_SCHEMA.COLUMNS
                            WHERE table_name = @YourTableName
                            FOR XML PATH('')
                       ), 1, 2, ''
                      )

SET @YourQuery  = 'SELECT '+@YourColumns+' FROM '+@YourTableName
PRINT @YourQuery  
SELECT * FROM YourTable

EXEC (@YourQuery)

OUTPUT:

SELECT COALESCE(CONVERT(varchar(max),c1),'NULL')+ COALESCE(CONVERT(varchar(max),c2),'NULL')+ COALESCE(CONVERT(varchar(max),c3),'NULL')+ COALESCE(CONVERT(char(23),c4,121),'NULL') FROM YourTable
c1          c2          c3    c4
----------- ----------- ----- -----------------------
1           2           abcde 2009-01-01 00:00:00.000
100         200         zzz   2009-12-31 23:59:59.000

(2 row(s) affected)


------------------------------------------
12abcde2009-01-01 00:00:00.000
100200zzz2009-12-31 23:59:59.000

(2 row(s) affected)