CREATE TABLE table_28250 ("No." FLOAT, "#" FLOAT, "Title" TEXT, "Director" TEXT, "Writer ( s ) " TEXT, "Original air date" TEXT, "Prod. code" FLOAT, "U.S. viewers  ( million ) " TEXT)

How many production codes are there for episode number 45?
SELECT COUNT("Prod. code") FROM table_28250 WHERE "No." = '45'
SELECT COUNT("Prod. code") FROM "table_28250" WHERE "No." = '45'