Invalid column name after PIVOT - sql

Question

I would like something like this:
42 | 41 | 31 | 32 | Name
----------------------------
O 42
X 41
P 32
Y 41
Z 41
The column headers that are pivoted are also the value in the name column. The various columns can have different statuses. This is what I have but I keep getting an error saying the ValveGroupName column is invalid.
DECLARE #cols AS NVARCHAR(MAX),
#query AS NVARCHAR(MAX)
select #cols = stuff((select ',' + quotename(ValveGroupName)
from dbo.adm_ValveGroup vgroup,
dbo.adm_Station station
where station.StationID = vgroup.StationID
and station.StationName in ('CBRN')
order by vgroup.ValveGroupName desc
for xml path(''), type).value('.', 'nvarchar(max)'), 1, 1, '')
set #query = 'select ValveGroupName,' + #cols + ' from
(
select vlog.status,
vgroup.ValveGroupName
from dbo.adm_Station station,
dbo.adm_ValveGroup vgroup,
dbo.valvegroup_log vlog
where station.StationID = vgroup.StationID
and vgroup.ValveGroupID = vlog.ValveGroupID
and station.StationName in (''CBRN'')
and vlog.logdate between ''2012-10-01'' and ''2012-10-30''
) x
pivot
(
max(status)
for ValveGroupName in (' + #cols + ')
) p '
execute (#query)
What's wrong with this query?

Answer 1

Since your ValveGroupName is becoming the new column names from the PIVOT, you normally won't include that in the final select list. Since you are basically "removing" the ValveGroupName to become the new columns, SQL Server doesn't have that column any longer so it throws an error.
The code would normally be:
set #query = 'select ' + #cols + '
from
(
select vlog.status,
vgroup.ValveGroupName
from dbo.adm_Station station
inner join dbo.adm_ValveGroup vgroup
on vgroup.ValveGroupID = vlog.ValveGroupID
inner join dbo.valvegroup_log vlog
on station.StationID = vgroup.StationID
where station.StationName in (''CBRN'')
and vlog.logdate between ''2012-10-01'' and ''2012-10-30''
) x
pivot
(
max(status)
for ValveGroupName in (' + #cols + ')
) p '
However, since you are aggregating a string that will return a single row for each ValveGroupName, if you want to return multiple rows, then you'll need to include a row_number:
set #query = 'select ' + #cols + '
from
(
select vlog.status,
vgroup.ValveGroupName,
seq = row_number() over(partition by vgroup.ValveGroupName
order by vlog.status)
from dbo.adm_Station station,
inner join dbo.adm_ValveGroup vgroup
on vgroup.ValveGroupID = vlog.ValveGroupID
inner join dbo.valvegroup_log vlog
on station.StationID = vgroup.StationID
where station.StationName in (''CBRN'')
and vlog.logdate between ''2012-10-01'' and ''2012-10-30''
) x
pivot
(
max(status)
for ValveGroupName in (' + #cols + ')
) p '
This change will allow you to return multiple rows in each column. Note: I also change the code to use INNER JOIN syntax instead of the comma joins, with the conditions in the WHERE clause.