Kue

The names of the letters, as now commonly spoken and written in English, are A, Bee, Cee, Dee, E, Eff, Gee, Aitch, I, Jay, Kay, Ell, Em, En, O, Pee, Kue, Ar, Ess, Tee, U, Vee, Double-u, Ex, Wy, Zee.

And there is [a] proverbial warning to mind your pees and kues.

SQL is pronounced either "ess-kue-ell" or "see-kwell" depending on your preference.