我有以下mysql表的布局:
+------+-------+-----+------+
| user |subject|month|change|
+------+-------+-----+------+
|Donald| Math | Jan | 3.15 |
+------+-------+-----+------+
| Mike | Math | Jan | 2.15 |
+------+-------+-----+------+
|Regan | Math | Jan | 3.00 |
+------+-------+-----+------+
|Donald| Engl | Febr|-3.05 |
+------+-------+-----+------+
| Mike | Engl | Febr| 3.00 |
+------+-------+-----+------+
|Regan | Engl | Febr|-3.00 |
+------+-------+-----+------+
|Donald| Geog | Jan | 3.00 |
+------+-------+-----+------+
| Mike | Geog | Jan |-2.15 |
+------+-------+-----+------+
|Regan | Geog | Jan | 3.60 | …我有两个表tb1和tb2我必须更新两个表的公共列，即user_level我对两个表都具有相同的条件，例如用户名。
所以我想这样更新：
UPDATE tb1, tb2 SET user_level=1 WHERE username="Mr.X"
但是它不起作用。什么是正确的mysql查询呢？