<p>MySQL 5.0.45</p>

<p>What is the syntax to alter a table to allow a column to be null, alternately what's wrong with this:</p>

<pre><code>ALTER mytable MODIFY mycolumn varchar(255) null;
</code></pre>

<p>I interpreted the manual as  just run the above and it would recreate the column, this time allowing null. The server is telling me I have syntactical errors. I just don't see them.</p>

You want the following:
```
```
ALTER TABLE mytable MODIFY mycolumn VARCHAR(255);
```
```
Columns are nullable by default.  As long as the column is not declared
```
UNIQUE
```
or
```
NOT NULL
```
, there shouldn't be any problems.