CREATE TABLE table_23308 ("Game" FLOAT, "Date" TEXT, "Opponent" TEXT, "Score" TEXT, "High points" TEXT, "High rebounds" TEXT, "High assists" TEXT, "Location" TEXT, "Record" TEXT)

On how many different dates was a game against Houston played?
SELECT COUNT("Date") FROM table_23308 WHERE "Opponent" = 'Houston'
SELECT COUNT("Date") FROM "table_23308" WHERE "Opponent" = 'Houston'