CREATE TABLE table_74322 ("No. in series" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" TEXT, "U.S. viewers  ( million ) " TEXT)

How many directors got 6.79 million U.S. viewers from their episodes?
SELECT COUNT("Directed by") FROM table_74322 WHERE "U.S. viewers (million)" = '6.79'
SELECT COUNT("Directed by") FROM "table_74322" WHERE "U.S. viewers (million)" = '6.79'