MySQL查询结果导出到文件的方法很多人都会，一般大家都会用 “SELECT INTO OUTFIL”将查询结果导出到文件，但是这种MySQL查询结果导出到文件方法不能覆盖或者添加到已经创建的文件。例如：
mysql> select 1 into outfile '/tmp/t1.txt'; Query OK, 1 row affected (0.00 sec) mysql> select 1 into outfile '/tmp/t1.txt'; ERROR 1086 (HY000): File '/tmp/t1.txt' already exists
还可以使用另外一种方法：
mysql> pager cat > /tmp/t1.txt PAGER set to 'cat > /tmp/t1.txt' mysql> select 1;! cat /tmp/t1.txt 1 row in set (0.00 sec) +---+ | 1 | +---+ | 1 | +---+
这样你能很方便的查询到2条sql的差异：
mysql> pager cat > /tmp/t01.txt PAGER set to 'cat > /tmp/t01.txt' mysql> select 12345 union select 67890; 2 rows in set (0.02 sec) mysql> pager cat > /tmp/t02.txt PAGER set to 'cat > /tmp/t02.txt' mysql> select 12345 union select 67891; 2 rows in set (0.00 sec) mysql> ! vimdiff -o /tmp/t0[12].txt 2 files to edit +-------+ | 12345 | +-------+ | 12345 | | 67890 | +-------+ /tmp/t01.txt +-------+ | 12345 | +-------+ | 12345 | | 67891 | +------+ /tmp/t02.txt