If provided, suggestion queries will be passed into your query function as the selection parameter. Typically this will be a WHERE clause for your database, and will contain a single question mark, which represents the actual query string that has been typed by the user. If not provided, then the user query text will be appended to the query Uri (after an additional "/".) Optional attribute.

Must be a string value, using '\\;' to escape characters such as '\\n' or '\\uxxxx' for a unicode character.

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

[Android Documentation]