使用case更新表中的mysql日期字段

I have this Match table:

我有这个匹配表：

| mid | Home | Away | dateUpdated | dateResultsEntered |
|  1  |  30  |  5   |   30/07/15  |      30/07/15      |
|  2  |  14  |  12  |   30/07/15  |      29/07/15      |
|  3  |  41  |  21  |   30/07/15  |      28/07/15      |
|  4  |  30  |  14  |   30/07/15  |      28/07/15      |
|  5  | NULL | NULL |   30/07/15  |      NULL          |
|  6  | NULL | NULL |   30/07/15  |      NULL          |
| mid | H