Which of the following is true regarding joins? Select all that apply. Most joins between tables that do not have a primary key-foreign key relationship are not valid. Joins between tables that do not have a primary key-foreign key relationship are valid in most circumstances. Outer joins are not valid. Invalid joins can create misinformation. Question 5 6.67pts Which of the following regarding unions is false? For a union operation to be possible, the two source tables must be union compatible. For a union operation to be possible, columns from both tables must be defined over the same domains. Tables in a union operation must have the same columns. Tables in a union operation must have columns of identical order and size