82.9. ERROR 1086 (HY000): File '/var/lib/mysql-files/order.txt' already exists
SELECT * FROM tabname INTO OUTFILE 不支持覆盖操作，这是MySQL从安全角度考虑的。
mysql> SELECT * FROM `order` INTO OUTFILE '/var/lib/mysql-files/order.txt';
ERROR 1086 (HY000): File '/var/lib/mysql-files/order.txt' already exists
