how to show query results in a datasheet in the same form?

Solution 1:

You can use Allen Browne's Search criteria form example as the basis for your search form. He provides a sample database in Access 2000 format and also a page which displays the code behind the form.

Edit: You wanted your query results presented as a datasheet in the same form. AFAIK, there is no way to display your search control on a form in datasheet view. If a continuous form is acceptable, Mr. Browne's example should be easier for you to adapt. But if you must have the query results in datasheet view, you can add a subform (with its Default View property set to Datasheet) to the search form. However, that approach will require you to apply the filter to the subform rather than the main form.