Question

I want a query to create a one row table with as many columns as there are rows in a table returned from a SELECT query., where the columns created have names which are values taken from some column of the SELECT query, and have values which are values taken from some other column of the SELECT query.

e.g.

If I have a table T1 with two columns as follows :

Field  Value
  A       1
  B       2
  C       3
  D       4

Then I want a query that will return the following one row table T2 as result :

COLUMN NAMES :    A       B       C       D
COLUMN VALUES:    1       2       3       4

Answer 1

A simple query to solve this:

SELECT  SUM(CASE C1 WHEN 'A' THEN C2 ELSE 0 END) AS 'A',
        SUM(CASE C1 WHEN 'B' THEN C2 ELSE 0 END) AS 'B',
        SUM(CASE C1 WHEN 'C' THEN C2 ELSE 0 END) AS 'C',
        SUM(CASE C1 WHEN 'D' THEN C2 ELSE 0 END) AS 'D'
FROM T1

An organic query:

DECLARE @C1 CHAR(1), @SQL VARCHAR(500)
DECLARE array CURSOR
    FOR SELECT C1
        FROM T1
        ORDER BY C1

OPEN array

FETCH NEXT FROM array
INTO @C1;
SET @SQL = 'SELECT  SUM(CASE C1 WHEN ''' + @C1 + ''' THEN C2 ELSE 0 END) AS ''' + @C1 + ''''
FETCH NEXT FROM array
INTO @C1;
WHILE (@@FETCH_STATUS = 0)
    BEGIN
        SET @SQL = @SQL + ', SUM(CASE C1 WHEN ''' + @C1 + ''' THEN C2 ELSE 0 END) AS ''' + @C1 + ''''
        FETCH NEXT FROM array
        INTO @C1
    END
SET @SQL = @SQL + 'FROM T1'

CLOSE array
DEALLOCATE array

EXEC(@SQL)