stringToMillis
Creates a STR_TO_MILLIS(expr) that will convert an ISO8601 datetime string into the number of milliseconds since the unix epoch. Valid date strings must start with a date in the form YYYY-MM-DD (time only strings are not supported).
Times can be of the form HH:MM, HH:MM:SS, or HH:MM:SS.FFF. Leading zero is not optional (i.e. 02 is ok, 2 is not). Hours are in 24-hour format. FFF represents milliseconds, and trailing zeros are optional (i.e. 5 == 500).
Time zones can be in one of three forms: (+/-)HH:MM (+/-)HHMM Z (which represents UTC)
Return
The STR_TO_MILLIS(expr) function.
Parameters
operand
The string expression.