How can I recommend this to folks who want to learn SQL if the mathmatical operators aren't defined before questions are asked about them. It's pretty hard to google set union if you've never seen it before... I'd love some more explanation for the math.

The union of two sets is the set of elements which are in either set (8).

The intersection of two sets is the set of elements which are in both sets (5).

I am not getting the editor for database . i am unable to answer. Please help me

Deberian hacer mejor la pregunta,no se entiende la solucion del problemas asi. No sabia si era union o interseccion

Union is either OR set Intersection is AND in both sets

How many elements are present in AuB? solution please

How many elements are present in ?

I made the same mistake speed reading the question. {1,2,3,4,5,6,7,8} is the union of both sets BUT the question is how many elements are in the union.

Actually, this problem need to first customize the input like below(Check the box of "Test against custom input"):

{1,2,3,4,5,6} {2,3,4,5,6,7,8}

where i should write the answer?

i just answered on the editorial box. but it didn't work.