Setting a Checkbox Marker

[nofue]

There's a checkbox control on my form, but I cannot get it to display a checkmark. I tried static variants as

 SELECT  'p' AS name,
          'Check This' AS label,
          'checkbox' AS type,
          4 AS width,
          1 AS value;

and also

'1' AS value
TRUE as value
NOT NULL AS value

but there is no checkmark.
I can set the checkmark in the form, it gets INSERTed to the db, I see the value (1) in the proper column, but how do I put a checkmark once I fetched (1) from the database?

This is the SELECT from the database, the right most value (1) is the column.

But in the form it looks like this:

[nofue]

Got it:

SELECT TRUE AS checked, ...