Changing Row/Column in Aggregate function in SQL - sql

Question

Here is a SQL Function - sorry about the complexity;
SELECT [Codes].[Description], RawData.FS, COUNT(*) As 'Total Units'
FROM RawData, Codes, Categories
WHERE RawData.ACR = Codes.Name
AND Codes.CategoryName = 'ACR'
GROUP BY [Codes].[Description], [RawData].[FS]
ORDER BY [RawData].[FS]
In description - there is a Codes table that contains codes that are used in the table RawData for each of the columns. A second table called Categories keeps track of all these columns and Codes.CategoryName is a FK to Categories.Name. Basically creating a single lookup table for each of the coded values in RawData.
The field RawData.FS has 3 values NULL, 1, and 2. The RawData.ACR has 3 values corresponding to the descriptions of less than 1 acre, 1-10 acres, > 10 acres. The query above gives the correct results
Description FS Total Units
House on less than one acre 57080
House on one to less than ten acres 4760
House on ten acres or more 880
House on less than one acre 1 31496
House on one to less than ten acres 1 4312
House on ten acres or more 1 360
House on less than one acre 2 594404
House on one to less than ten acres 2 74688
House on ten acres or more 2 9104
The challenge here is to redo the SQL so that instead of 3 sets of 3 rows, theirs is a column corresponding to values of FS. In other words the header would be (for the first row);
Description FS=NULL FS=1 FS=2
House on less than one acre 57080 31496 594404
As a little bit more help - here is the SQL to create the Category and Code structure
CREATE TABLE Categories (
[Name] NVARCHAR(50) PRIMARY KEY,
[Description] NVARCHAR(200)
)
CREATE TABLE Codes (
[Name] NVARCHAR(50),
[CategoryName] NVARCHAR(50) FOREIGN KEY REFERENCES Categories(Name),
[Description] NVARCHAR(200) )
Every field in RawData is coded (in fact the data dictionary is at http://www.census.gov/acs/www/Downloads/data_documentation/pums/DataDict/PUMS_Data_Dictionary_2009-2011.pdf ). This is one of those classic SQL puzzles.

Answer 1

It sounds like you want to do the following which will pivot the FS values into columns:
SELECT [Codes].[Description],
sum(case when RawData.FS is null then 1 else 0 end) FS_null,
sum(case when RawData.FS = 1 then 1 else 0 end) FS_1,
sum(case when RawData.FS = 2 then 1 else 0 end) FS_2
FROM RawData
INNER JOIN Codes
ON RawData.ACR = Codes.Name
INNER JOIN Categories
ON Codes.CategoryName = Categories.Name
WHERE Codes.CategoryName = 'ACR'
GROUP BY [Codes].[Description]

Answer 2

Untested but it seems a case(s) and a subselect would work.
Select description,
case when fs is null then total_units end as 'FS=Null',
CASE WHEN fs = 1 then total_units end as 'FS=1',
case when fs = 2 then total_units end as 'FS=2'
FROM (
SELECT [Codes].[Description],
RawData.FS, COUNT(*) As 'Total_units'
FROM RawData, Codes, Categories
WHERE RawData.ACR = Codes.Name
AND Codes.CategoryName = 'ACR'
GROUP BY [Codes].[Description])
ORDER BY description