CREATE TABLE table_52428 ("Home team" TEXT, "Home team score" TEXT, "Away team" TEXT, "Away team score" TEXT, "Venue" TEXT, "Crowd" FLOAT, "Date" TEXT)

When collingwood played as the home team who was the away team?
SELECT "Away team" FROM table_52428 WHERE "Home team" = 'collingwood'
SELECT "Away team" FROM "table_52428" WHERE "Home team" = 'collingwood'