Need to get the result using for loop

[Xplore]

I have Parent Table like,\[code\] Id Sl No 27 1 27 2 28 1 28 2\[/code\]I have Child table like\[code\] Id Slno Result 27 1 y 27 2 y 27 3 N 28 1 Y\[/code\]Here in Parent table for Id ->27,the slno are 1 & 2. In child table for Id->27, the slno are 1 ,2, 3.where 3 is not in parent table. so now i should display result as 'N'. I want this using For loop. Please help me on this.