hey !

correct me if i am wrong, but the 2nd statement is same as the 1st

 

SELECT AVG(FEES) FROM STUDENT GROUP BY GRADE HAVING SUM(FEES)>1500;   what does GROUP BY has to do here ??? we r selecting average of fees. the output will be a number. so, both r same.   i hope u got it ! rate me if found useful !!!

the groupby clause combines all records that have identical value in a particular field or a group of fields.

in 1st case only d sum condition will be checked

but in d 2nd the condition for each grade grouped will also be checked.

also in 2nd case the having clause is used since having clause works only wid groups.

hope im rite!!

ofcoooourse they are different in the first case all the fees are added and if it is greater than 1500 then the avg of all the fees is printed . in the second case the fees of each grade is added and if the sum is > 1500 then the avg. of feesof that grade is printed