How to query records number in a joint query? : <p>for example,I have 2 tables student &amp; report, "student" log student info,"report" log every student's school report,a student has more than one reports so report table has a foreign key "sid" referenced to student table,now I want to query every student's info and his report number,so how can I do the query in one query?  Currently I had to use two queries.</p>
