CREATE TABLE table_57928 ("Episode" TEXT, "Air Date" TEXT, "Rating" FLOAT, "Share" FLOAT, "Rating/Share 18\\u201349" TEXT, "Viewers  ( m ) " FLOAT, "Timeslot Rank" FLOAT, "Night Rank" TEXT, "Overall Rank" FLOAT)

What is the smallest share for a timeslot ranking less than 4 and fewer viewers than 8.78 million?
SELECT MIN("Share") FROM table_57928 WHERE "Viewers (m)" < '8.78' AND "Timeslot Rank" < '4'
SELECT MIN("Share") FROM "table_57928" WHERE "Timeslot Rank" < '4' AND "Viewers (m)" < '8.78'