2 votes 2 votes A) 3 B) 2 C) 1 D) 0 iita asked Feb 5, 2017 iita 1.0k views answer comment Share Follow See all 15 Comments See all 15 15 Comments reply skraj commented Feb 5, 2017 reply Follow Share Is it answer A 0 votes 0 votes Sanjay Sharma commented Feb 5, 2017 reply Follow Share WHAT IS T1 HERE 0 votes 0 votes iita commented Feb 5, 2017 reply Follow Share answer is A but how the where condition is not satisfied here.... 0 votes 0 votes papesh commented Feb 5, 2017 reply Follow Share Because of count(*). They did mistake while copying question.In place of T1 there is R. Count(*) return always non negative values so exist return always true over here. 0 votes 0 votes iita commented Feb 5, 2017 reply Follow Share since it is a correlated query..so count will return 0 everytime which is empty...isn't it..?? 0 votes 0 votes Devshree Dubey commented Feb 5, 2017 reply Follow Share count(*) will return a 0 value since d condition inside in d Exist clause isn't met. Am I right? 0 votes 0 votes Devshree Dubey commented Feb 5, 2017 reply Follow Share So if u see accordingly exists clause evaluates to false. D answer shud undoubtedly be 0. Correct me if I m wrong. Okay. :) 0 votes 0 votes papesh commented Feb 5, 2017 reply Follow Share Exist returns False value wheb it compares with null value else returns True. A.is right answer. 0 votes 0 votes Sanjay Sharma commented Feb 5, 2017 reply Follow Share can given subquery execute independently i mean no reference of R here in from clause 0 votes 0 votes Devshree Dubey commented Feb 5, 2017 reply Follow Share In short wat u want to convey is dat irrespective of d condition given either in case of a NULL value exist will return true. Coz in d above table there is no NULL value. In short, if a table doesn't has a NULL value and it is clubbed up with exist clause it returns true. If dis be den in tat case, d answer shud be A. As per ur explanation. :) 0 votes 0 votes Devshree Dubey commented Feb 5, 2017 reply Follow Share subquey returns a zero record since d condition evaluates to false. 0 votes 0 votes target2017 commented Feb 6, 2017 reply Follow Share "S.E > 10" - always false. So count(*) should be zero, then how exist will return true? 0 votes 0 votes Devshree Dubey commented Feb 6, 2017 reply Follow Share Yes even I m wondering. In tat case d answer is a 0 value returned by d subquery. :) 0 votes 0 votes Arjun commented Feb 19, 2017 reply Follow Share Exists <0> returns TRUE. See its English meaning - it checks for existence- not what value exists. This is similar to null set and a set containing empty string in TOC. 2 votes 2 votes Dexter commented Feb 19, 2017 reply Follow Share So now non null value exist for each one of them . So it will return 3 :) 2 votes 2 votes Please log in or register to add a comment.