使用没有PK的另一个表的值更新表

I have two tables

我有两张桌子

+-------+----+
| name  | id |
+-------+----+
| < -5  |  1 | 
| -2    |  5 |
| -1    |  6 |
| 0     |  7 |
| + 1   |  8 |
| + 3   |  9 |
| + 5   | 10 |
| > 60  | 17 |
+-------+----+
Table 2: 
+------------+------------+-------------------+-------------------+
| diff_date1 | diff_date2 | variance_id_date1 | variance_id_date2 |
+------------+------------+-------------------+-------------------+
|          0 |          0 |                 0 |                 0 |
|        -21 |        -21 |                 0 |                 0 |
|          5 |          5 |                 0 |                 0 |
|         58 |         58 |                 0 |                 0 |
|          4 |          4 |                 0 |                 0 |
+------------+------------+-------------------+-------------------+
+-------+----+
|