Alter a MySQL column to be AUTO_INCREMENT

Question

I’m trying to modify a table to make its primary key column `AUTO_INCREMENT` after the fact. I have tried the following SQL, but got a syntax error notification. ``` ALTER TABLE document ALTER COLUMN document_id AUTO_INCREMENT ``` Am I doing something wrong or is this not possible? ``` +--------------------+ | VERSION() | +--------------------+ | 5.0.75-0ubuntu10.2 | +--------------------+ ```

Accepted Answer

```
ALTER TABLE document MODIFY COLUMN document_id INT auto_increment
```

Alter a MySQL column to be AUTO_INCREMENT

Solution

Problem