SQL doubt

Question

what will be the output of the query ?

SELECT A, Avg(B)

FROM R 

GROUP BY A:

Table R

A	B	C
a1	b1	80
NULL	b2	90
a3	b5	40
NULL	b2	30
a1	b1	90
a3	b6	NULL

 

Answer 1

A	B(avg)
a1	b1
a3	(b5+b6)/2
null	b2
null	b2

in SQL every null treated as different 

Comments

i also think the same....

Answer 2

Avg(B)	A(group by A)
(b1+b1)/2	a1
(b5+b6)/2	a3
b2	Null
b2	Null

 

Null is non  zero and two null value may not same 

Null is a sequence of ASCII character assigned by DBMS in such way two nulls may not same  --->(Code Rule)

 

Comments

I have read somewhere that every null is treated as different..

---

yes every null will be treated as different

---

then I think there must be 4 rows in the output Isn't it?