Access database "Operation must use an updatable query" __ Database

And today I have this error. "The operation must use an updatable query " Here I sorted out the reasons and solutions, you will encounter the same problems in the future can try a similar solution.

Online Baidu A lot, there is no role, most of them are said permission issues, the change is also very troublesome, and finally did not solve, the following specifically said my situation:

There are field IDs, Roomnum, username in table A

There are field IDs, remark, username in table B

Now that the field room of table A is empty, you need to find remark from the username in table A to table B, and then update to table A (if there are no users with duplicate names)

Use the general UPDATE statement as:

Update A as T1 set t1.roomnum = (select Max (username) from B as t2 where t2.username = t1.username)

This SQL statement is not allowed in the Access database and prompts " action must use an updatable query "

So I thought, another UPDATE statement, as follows:

UPDATE A as T1, (SELECT username,remarkfrom B) as t1 SET t1.roomnum = T2.remark
WHERE t1.username = t2.username;

The problem has been solved ^_^