The ODBC recordset is the set of records from the datasource. If no filter is present, it encompasses the whole datasource. If a filter is present, it is only the subset of records for which the filter condition is satisfied.
A filter is made up of a condition and a parameter that the '?' in the condition stands for. Some examples :
|condition (filter)||paramter||result : only records|
|NAME like ?||du*||whose NAME starts with "du"|
|GROUP = ?||501||whose GROUP = 501|
|NAME < ?||d||whose first character in NAME is after 'd'|
The result can be sorted.