Field type codeeditor for sql

I have successfully created a custom add on.
The addon queries the database for records and displays the record count as a badge on a button.
Thus i used a field
'type' => 'codeeditor',
'syntax' => 'htmlmixed'
for sql query configuration.
Works like a charm until i try to add "smaller than" in the query, such as <= now() .
In this case the interpreter takes this as a html statement- which is expected.
What field type and syntax attribute do you reccommend to take, which is not interpreted?
Is there a developer documentation where I can see those field types and attributes?