F_DATETOSTR

Entrypoint datetostrlang not compatible with UTF-8 - use U_DATE2STRLANG

   Input      TIMESTAMP        date optionally time
              CSTRING(254)     pattern
   Output     CSTRING(254)     date formatted with parameter 2

   Pattern for parameter 2 (similar to c-function strftime):
        %% - character %,
        %c - date and time,
        %x - date,
        %d - day of a month (01-31),
             %j - day of year (000-366),
        %w - day of week (0-6), 0 - Sunday,
        %U - number of week in one year (00-53), Sunday - the first day of week,
        %W - number of week in one year (00-53), Monday - the first day of week,
        %a - the short name of day of week,
        %A - the full name of day of week,
        %m - month (01-12),
        %b - the short name of day of month,
        %B - the full name of day of month,
        %y - year (00-99),    %Y - four-digit year,
        %X - time,
        %H - hour (00-23),   %I - hour (01-12),
        %M - minute (00-59),
        %p - AM or PM,
        %S - second (00-59).
   TestSQL
   SELECT '10 February 2004, 08:23:00' AS ISCORRECT, F_DATETOSTR('10.02.04 08:23', '%d %B %Y, %X') FROM RDB$DATABASE;
   SELECT NULL AS ISCORRECT, F_DATETOSTR(NULL, NULL) FROM RDB$DATABASE;