database - oracle systimestamp (sysdate) to milliseconds

Question

Could you provide implementation of stored function to get current systimestamp as milliseconds.
Something I can use like

select current_time_ms from dual;

and get the difference, measured in milliseconds, between the current time and midnight, January 1, 1970 UTC.

Thanks.

Answer 1

• DB timezone agnostic
• with milliseconds
• works in XE

    function current_time_ms
        return number
    is
        out_result number;
    begin
        select extract(day from(sys_extract_utc(systimestamp) - to_timestamp('1970-01-01', 'YYYY-MM-DD'))) * 86400000 
            + to_number(to_char(sys_extract_utc(systimestamp), 'SSSSSFF3'))
        into out_result
        from dual;
        return out_result;
    end current_time_ms;