Multiple choice technology databases

In which case would you use a FULL OUTER JOIN?

  1. Both tables have NULL values

  2. You want all unmatched data from one table

  3. You want all matched data from both tables

  4. You want all unmatched data from both tables

  5. One of the tables has more data than the other

  6. You want all matched and unmatched data from only one table
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A FULL OUTER JOIN returns all matched rows from both tables PLUS all unmatched rows from both tables (with NULLs where there's no match). It's the combination of LEFT OUTER JOIN and RIGHT OUTER JOIN, useful when you need complete data from both sides regardless of matching.

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