With the help of UNION, can we diplay data from 3 different tables..?

Answer 1

Yes u can display data from more then two table using UNION to get a combination of all three dataset into one. But only if the column from all the table are of same name and same data type. if column name is not same then u can use AS keyword to customize the column name.

Answer 2

Probably, just as we can have many statements combined with many ands or ors.