SQL : Select a dynamic number of rows as columns

Question

I need to select static colums + a dynamic number of rows as columns in SQL

TABLE 1
-------
HotelID
BlockID
BlockName

TABLE 2
-------
BlockDate (unknown number          


        

Answer 1

What you require is a pivot query, to convert row data into columnar:

  SELECT t.hotelid,
         t.blockid,
         t.blockname,
         MAX(CASE WHEN t2.blockdate = '02-10-10' THEN t.numberofrooms ELSE NULL END) AS 02_10_10,
         MAX(CASE WHEN t2.blockdate = '02-11-10' THEN t.numberofrooms ELSE NULL END) AS 02_11_10,
         MAX(CASE WHEN t2.blockdate = '02-12-10' THEN t.numberofrooms ELSE NULL END) AS 02_12_10,
         ...
    FROM TABLE_1 t
    JOIN TABLE_2 t2
GROUP BY t.hotelid, t.blockid, t.blockname

1. Mind that there's nothing to link the tables - realistically TABLE_2 needs hotelid and blockid attributes. As-is, this will return the results of TABLE_2 for every record in TABLE_1...

2. The database is important, because it will need dynamic SQL to create the MAX(CASE... statements