CREATE TABLE table_71778 ("Date" TEXT, "Opponent" TEXT, "Score" TEXT, "Loss" TEXT, "Attendance" TEXT, "Record" TEXT)

What was the date of the game with the Kansas City Royals when the Blue Jays record was 18-12?
SELECT "Date" FROM table_71778 WHERE "Opponent" = 'royals' AND "Record" = '18-12'
SELECT "Date" FROM "table_71778" WHERE "Opponent" = 'royals' AND "Record" = '18-12'