CREATE TABLE table_21452 ("Game" FLOAT, "Date" TEXT, "Team" TEXT, "Score" TEXT, "High points" TEXT, "High rebounds" TEXT, "High assists" TEXT, "Location Attendance" TEXT, "Record" TEXT)

How many different items appear in the high points column when the location attendance was US Airways Center 18,422?
SELECT COUNT("High points") FROM table_21452 WHERE "Location Attendance" = 'US Airways Center 18,422'
SELECT COUNT("High points") FROM "table_21452" WHERE "Location Attendance" = 'US Airways Center 18,422'