Do you actually mean you want to export 18 million rows to an Excel file, or do you you want to export 18 million rows to, say, a CSV file
to my knowledge excel cannot handle a 18 million row file
in any event use a query to select waht rows you want and save the output to a file.
if you need the output in Excel, then send it as chunks of data that Excel can read
OR import the data directly into an Excel workbook using an ODBC query INSIDE Excel
.. that assume that you have Access to a MySQL server using the MySQL command line or a SQL tool such as MySQL's own Workbench or similar.
failing that you could export a query using a scripting language
or you could could create the required output in the query (using commas and or appropriate delimiters).
to setup your query its going to be soemthign like
replace the italicised words with:-
SELECT my, column, list FROM mytable
WHERE AcctStartTime >= '2015/01/01'
the names of your columns (my, column, list)
the name of your table (mytable)
you may need to coerce the date literal ('2015/01/01') using the STR_TO_DATE function for the above to work
I'd rather be riding on the Tiger 800 or the Norton