SQLCMD Exporting 16.5 Million Rows
You'll probably want to do this with bcp, which is intended for this kind of thing. It would be something like this:

bcp "SELECT ROW_KEY, ISNULL(CARRIER_ID, ''),ISNULL(CONVERT(VARCHAR(19),ORDER_DATETIME,120),''),ISNULL(HEIGHT, ''),ISNULL(RESIDENTIAL_CHARGE, '') FROM MYTABLE" queryout OUTPUT_FILE.txt -c -S &lt;servername&gt; -U &lt;login_name&gt; -P &lt;password&gt;


Replace -c with -w if you're dealing with nvarchar/nchar, and want Unicode output.