Which type of JOIN is used to returns rows that do not have matching values?

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Editor">Editor Staff asked 2 years ago

Which type of JOIN is used to returns rows that do not have matching values?

  1. Natural JOIN
  2. Outer JOIN
  3. EQUI JOIN
  4. All of the above
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1 Answers
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Editor">Editor Staff answered 2 years ago

Answer:
B.   Outer JOIN
Explanation:
OUTER JOIN is the only join that returned the unmatched rows in one or both tables. It can be classified into the following types:

  • LEFT JOIN that shows only the unmatched rows from the left table.
  • RIGHT JOIN that shows only the unmatched rows from the right table.
  • FULL OUTER JOIN that shows the unmatched rows from both tables.

EQUI JOIN shows records for equality or matching column(s) values of the relative tables.
A Natural join can only be performed if at least one common attribute exists between two relations (the attributes should be the same name and domain).