  We study the specializations of parameters in Koornwinder polynomials to
obtain Macdonald polynomials associated to the subsystems of the affine root
system of type $(C_n^\vee,C_n)$ in the sense of Macdonald (2003), and summarize
them in what we call the specialization table. As a verification of our
argument, we check the specializations to type $B,C$ and $D$ via Ram-Yip type
formulas of non-symmetric Koornwinder and Macdonald polynomials.
