Question 11 :
Outer join is the same as equi-join, except one of the duplicate columns is eliminated in the result table.
Question 12 :
A correlated subquery is where the outer query depends on data from the inner query.
Question 13 :
A function returns one value and has only output parameters.
Question 14 :
With the UNION clause, each query involved must output the same number of columns, and they must be UNION compatible.