Filter
Filter is an optional field for use by a system administrator. To properly use this field, you should be familiar with SQL "where" clause formats and the database schema. The filter is a SQL "where" clause used to restrict the rows replicated from the table based on filter criteria that you set.
For example, you might want to replicate only items whose code is set to "A", where "code" is a column in the "item_all" table. You could add the following filter to the "item_all" table's row in Replication Categories:
bt.code = 'A'
Note: bt (base table) is required as an alias in this case.
This restricts the rows replicated from that table to only those containing an A in the code column.