Consider a relational database containing the following schemas. The primary…

Consider a relational database containing the following schemas.

The primary key of each table is indicated by underlining the constituent fields.

SELECT s.sno, s.sname FROM Suppliers s, Catalogue c WHERE s.sno=c.sno AND cost > (SELECT AVG (cost) FROM Catalogue WHERE pno = ‘P4’ GROUP BY pno) ;

The number of rows returned by the above SQL query is