SQL Server - Dynamic Pivot

Question

I\'m needing some help. I have two columns, Place and Name, I want a count of Name for each place. Currently the data would look like:

Place | Name
100     OK
10         


        

Answer 1

Your current query is close but since you want to count the number of names you can just use that as the aggregate function, instead of using the CASE statement in your subquery and then averaging.

My suggestion would always be to write the query as a static version first before trying to write a dynamic SQL server, mainly to get the syntax correct:

select place, Bad, New, OK
from
(
  select place, name
  from info_table
) d
pivot
(
  count(name)
  for name in (Bad, New, OK)
) p;

See SQL Fiddle with Demo. Once you have the logic correct, then you can easily turn this to dynamic SQL:

DECLARE @cols AS NVARCHAR(MAX);
DECLARE @query AS NVARCHAR(MAX);

SELECT @cols = STUFF((SELECT distinct 
                        ',' +
                        QUOTENAME(NAME)
                 FROM INFO_TABLE with (nolock)
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'');

SET @query = ' SELECT PLACE ,  ' + @cols + ' 

FROM 
(
   SELECT NAME, PLACE
   FROM INFO_TABLE with (nolock)
) t
PIVOT
( 
  count(name)
  FOR NAME IN (' + @cols + ' )
) 
p ' ;

Execute(@query);

See SQL Fiddle with Demo