CREATE TABLE table_28172 ("No." FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" TEXT, "U.S. viewers  ( million ) " TEXT)

What episode number was written by Anthony Sparks?
SELECT MIN("No.") FROM table_28172 WHERE "Written by" = 'Anthony Sparks'
SELECT MIN("No.") FROM "table_28172" WHERE "Written by" = 'Anthony Sparks'