1 1 vote Consider the following instance R. A 1 2 3 4 B Null 1 2 2 The number of tuples returned by the following SQL query is _____________. > select * from R as R1 where not exists (select * from R) where B = R1.A Databases databases sql virtual-gate-test-series + – Naveen K Verma 1.7k views answer comment Share Follow Print See all 11 Comments 11 11 Comments reply Show 8 previous comments hs_yadav commented Jan 10, 2018 reply Follow flag yes undefined .... let comparison is like this.... any Number =NULL (here we r not sure about the value of NULL therefor False) Number>NULL(again we r not sure about the value of NULL therefor False) Number<NULL(again we r not sure about the value of NULL therefor False)..... therefor we say that the comparison with NULL gives undefine ... 0 0 replyShare Ashwin Kulkarni commented Jan 10, 2018 reply Follow flag Then NOT exist (undefined) will not return any rows 0 0 replyShare sai charan chakrala commented Feb 6, 2019 reply Follow flag I think the answer should be 2 as the two tuples with A as 3 and 4 should be returned as they do not have an equivalent value in B. 0 0 replyShare Please log in or register to add a comment.
0 0 votes there is a mistake in parathezisation...it will be 2 DeadMann answered Oct 30, 2022 DeadMann comment Share Follow 0 reply Please log in or register to add a comment.
