CREATE TABLE table_57887 ("Home team" CLOB, "Home team score" CLOB, "Away team" CLOB, "Away team score" CLOB, "Venue" CLOB, "Crowd" FLOAT, "Date" CLOB)

When did Richmond play an away game against Collingwood?
SELECT "Date" FROM table_57887 WHERE "Away team" = 'richmond'
SELECT "Date" FROM "table_57887" WHERE "Away team" = 'richmond'