Sorry, i do not understand the problem:

in your datasource you have following picture:
myFields
  queryFields
  dataFields

under the node queryFileds you have all Field which you can use to run a
query against the database.

put a field for account number from query node in your form
put a button whit property "run query" in your form

put the first childnode of dataFileds in your form as "section with
controls" (datasection)

preview the form
put a valid account number into your queryfield you inserted into the form
push the button.

if there is a record it will be show in the data section

i hope i could help you