这两表格怎么合并？

date ON 1W 2W 1M 3M 6M 9M 1Y
0 2007-01-04 14310 15238 21667 25774 28077 28685 29306 30022
1 2007-01-05 14047 15057 20492 25717 28079 28686 29305 30023
2 2007-01-08 13721 14524 20303 25588 28080 28687 29306 30023
3 2007-01-09 13546 14405 19781 25572 28083 28687 29307 30024
[4 rows x 9 columns]
date ON 1W 2W 1M 3M 6M 9M 1Y
0 2008-01-02 25844 28624 29112 36792 44404 44662 45183 45853
1 2008-01-03 22990 29370 30068 34737 44427 44668 45222 45884
2 2008-01-04 22990 28432 29972 33918 44446 44699 45238 45905
3 2008-01-07 22723 27214 29813 33197 44472 44748 45272 45930
4 2008-01-08 20744 23719 28252 33025 44565 44879 45330 45989
5 2008-01-09 19088 23985 28256 33371 44618 44935 45370 46057
6 2008-01-10 18859 24238 28114 33555 44613 45064 45417 46110
[7 rows x 9 columns]