This parameter specifies the SQL query to execute when performing a full database collection update. The syntax of the SQL query must conform to that required by the underlying database. Creation of a database view for the purpose of search is recommended to simplify the query.
The query is expected to contain a column name matching the
value and this column’s value will be used to identify the record. If several records share the same
value, only one (the latest in the result set) will be indexed.
Each row resulting from the SQL query will be indexed, and the column names will be used as XML element names to allow metadata configuration to control the indexing.
Please note that with most database drivers, a semicolon (;) should not be included at the end of the query.