Times in Hive are plain Ints — Unix seconds — so they need no type of their own to pass around, store or compare. now() reads the clock; timezone() and timezoneOffset() say where the program thinks it is; format renders a time in local time with a strftime-style template — %Y, %m, %d, %H, %M, %S and the rest. An escape it doesn't recognise passes straight through rather than failing.