CREATE TABLE table_28078 ("Series #" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" TEXT, "U.S. viewers  ( million ) " TEXT)

How many episodes with the production code CA106 are there?
SELECT COUNT("Written by") FROM table_28078 WHERE "Production code" = 'CA106'
SELECT COUNT("Written by") FROM "table_28078" WHERE "Production code" = 'CA106'