  The Askey--Wilson polynomials are the most general classical orthogonal
polynomials that are known and the Nassrallah--Rahman integral is a very
general extension of Euler's integral representation of the classical $_2F_1$
function. Based on a $q$-series transformation formula and the
Nassrallah--Rahman integral we prove a $q$--beta integral which has twelve
parameters, with several other results, both classical and new, included as
special cases. This $q$-beta integral also allows us to derive a curious double
$q$--series transformation formula, which includes one formula of Al--Salam and
Ismail as a special case
