A filter is optional. It relies on a source specific syntax for filtering out records from source or target. The filter can reference execution parameters.
For a file data sources (delimited, fixed width & Excel) the syntax conforms to the .NET frameworks RowFilter on a DataView
For Salesforece syntax is the SOQL where clause (without the where expression)
For Dynamics syntax is the OData $filter clause (without the $filter=expression)
For Cinchy syntax is the CSQL where clause (without the where expression)
For SqlServer the syntax is the T-SQL where clause (without the where expression)
This is only available if using a table, not a query. For queries, include the filter in the query itself. Note, there can only be one <Filter> for each source or target. To specify more than one condition, use AND/OR to allow logical combination of multiple expressions.
<Filter>[net worth] > 100000 </Filter>
All the records with [net worth] > 100000 are only synced in to the target table.