How to concatenate all columns in a select with SQL Server

问题

I need my select to have a pattern like this:

 SELECT '<text> ' + tbl.* + ' </text>' FROM table tbl;

The ideal solution would have all the columns separated by a comma in order to have that output:

SQL result for Table 1 with two columns:

'<text>col1, col2</text>'

SQL result for Table 2 with three columns:

'<text>col1, col2, col3</text>' 

I tried to use the CONCAT(...) function like this:

SELECT CONCAT('<text>', tbl.*, '</text>')
FROM table2 tbl

But I understand it is not so simple because the variable number of columns.

Is there any simple solution to address that problem?

I am using SQL Server 2008 R2.

回答1:

Any number of columns for a given tablename; If you need column names wrapped with <text>

DECLARE @s VARCHAR(500)

SELECT @s =  ISNULL(@s+', ','') + c.name   
FROM  sys.all_columns c join sys.tables  t 
            ON  c.object_id = t.object_id
WHERE t.name = 'YourTableName'

SELECT '<text>' + @s + '</text>'

SQL Fiddle Example here

-- RESULTS 
<text>col1, col2, col3,...</text>

If you need select query result set wrapped with <text> then;

SELECT @S =  ISNULL( @S+ ')' +'+'',''+ ','') + 'convert(varchar(50), ' + c.name    FROM 
       sys.all_columns c join sys.tables  t 
       ON  c.object_id = t.object_id
WHERE t.name = 'YourTableName'


EXEC( 'SELECT ''<text>''+' + @s + ')+' + '''</text>'' FROM YourTableName')

SQL Fiddle Example here

--RESULTS
<text>c1r1,c2r1,c3r1,...</text>
<text>c1r2,c2r2,c3r2,...</text>
<text>c1r3,c2r3,c3r3,...</text>

回答2:

SQL Fiddle

MS SQL Server 2008 Schema Setup:

create table YourTable
(
  ID int identity primary key,
  Name varchar(50),
)

insert into YourTable values
('Name 1'),
('Name 2'),
('Name 3'),
('Name 4'),
('Name 5')

Query 1:

select (
       select (
              select ', '+T2.N.value('./text()[1]',  'varchar(max)')
              from (
                   select T.*
                   for xml path(''), type
                   ) as T1(N)
                cross apply T1.N.nodes('/*') as T2(N)
              for xml path(''), type
              ).value('substring(./text()[1], 3)',  'varchar(max)')
       for xml path('text'), type
       )
from YourTable as T

Results:

|               COLUMN_0 |
--------------------------
| <text>1, Name 1</text> |
| <text>2, Name 2</text> |
| <text>3, Name 3</text> |
| <text>4, Name 4</text> |
| <text>5, Name 5</text> |

回答3:

I tried a more generic approach

Create Procedure P_GetConcatColumns(@tablename varchar(200),@Seperator Varchar(20),@StartTag Varchar(20),@EndTag Varchar(20),@WhereString Varchar(400),@OrderString Varchar(400)) as


DECLARE @TmpTableName VARCHAR(100),
        @Columns NVARCHAR(4000),
        @SQL NVARCHAR(MAX),
        @GENNAME VARCHAR(100)

Select  @GENNAME='##'+Replace(Cast(NewID() as Varchar(40)),'-','')

IF OBJECT_ID('tempdb.dbo.' + @GENNAME) IS NOT NULL
BEGIN
    EXEC('DROP TABLE ' +@GENNAME);
END




Select @SQL='SELECT TOP 1 * INTO '+@GENNAME+' FROM ' + @tablename
Exec (@SQL)



SET @TmpTableName = 'tempdb.dbo.' + @GENNAME
SELECT @Columns = 
    STUFF(
    (
    SELECT '+' + @Seperator + '+CAST(Coalesce(' + c.name + ','''') AS VARCHAR(MAX))' + CHAR(13)
    FROM tempdb.sys.columns c
    WHERE c.[object_id] = object_Id(@TmpTableName)
    FOR XML PATH(''),TYPE
    ).value('.','VARCHAR(MAX)')
    ,1,len(@Seperator)+2,'')

--SET @SQL = N'SELECT ' +''''+ @StartTag +''''+'+'+ @Columns +''''+'+'+ @EndTag + ''' FROM ' + @tablename 
SET @SQL = N'SELECT ''' +@StartTag+ '''+'+ @Columns +'+'''+ @EndTag + ''' FROM ' + @tablename 
+' '+Coalesce(@WhereString,'')
+' '+Coalesce(@OrderString,'')
Print @SQL
EXEC sp_executeSQL @SQL


--ExampleCall P_GetConcatColumns 'Arten',''',''','<test>','</test>','where id>1','Order by ID desc'

回答4:

Try the code below:

SELECT Stuff(
(SELECT N', ' + COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS 
where TABLE_NAME = 'YourTableName' FOR XML PATH(''),TYPE)
.value('text( [1]','nvarchar(max)'),1,2,N'')

来源：https://stackoverflow.com/questions/13761337/how-to-concatenate-all-columns-in-a-select-with-sql-server