Concatenate Rows for one column SQL [duplicate]

问题

I am using following query to extract appointment data:

SELECT app.subject, AL.locationName
FROM FilteredAppointment app
INNER JOIN appointmentlocation AL ON app.activityid = AL.appointment
WHERE app.scheduledstart='2013-07-06 15:00:00.000'

The output is as follows with 2 rows (same appointment with two different locations):

How can i modify this query to display only one row with two locations concatenated with comma like below:

Column1: (MZN; OTV)*...
Column2: Room1,Room2

Thanks

回答1:

what you need is SQL Join and concatenate rows, there are many questions on SO about it. There's no easy way to do this in SQL Server, but here some tricks:

Concatenate by using select for xml

select
    app.subject,
    stuff(
       (
           select ', ' + AL.locationName
           from appointmentlocation as AL
           where AL.appointment = app.activityid
           for xml path(''), type
       ).value('.', 'nvarchar(max)')
    , 1, 2, '') 
from FilteredAppointment as app
where app.scheduledstart='2013-07-06 15:00:00.000'

if you have only one record from FilteredAppointment to concatenate, you could use aggregating into variable:

declare @locations nvarchar(max), @activityid int

select @activityid = ???

select @locations = isnull(@locations + ', ', '') + AL.locationName
from appointmentlocation as AL
where AL.appointment = @activityid

print @locations

回答2:

This example will help you .. or wait until I makequery for you

  USE app.subject,
    SELECT      AL.locationName AS [Loc],
                STUFF((    SELECT ',' + SUB.Name AS [text()]
                            – Add a comma (,) before each value
                            FROM appointmentlocation AL
                            WHERE
                            app.activityid = AL.appointment

                            FOR XML PATH('') – Select it as XML
                            ), 1, 1, '' )
                            – This is done to remove the first character (,)
                            – from the result
                AS [Sub Categories]
    FROM  FilteredAppointment app

回答3:

SELECT app.subject, GROUP_CONCAT(AL.locationName, ', ') AS LocationName
FROM FilteredAppointment app
INNER JOIN appointmentlocation AL ON app.activityid = AL.appointment
WHERE app.scheduledstart='2013-07-06 15:00:00.000'
GROUP BY app.subject

Untested

回答4:

I can't test it right now but I think this might do the work

select subject, 
       group_concat(name separator ',') Newcolumn
  from table
 group by subject

来源：https://stackoverflow.com/questions/17990986/concatenate-rows-for-one-column-sql

标签

sql

sql-server-2008-r2