Joining Multiple Tables Flashcards
6 cards from real 1Z0-071 practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
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What is the main advantage of using table aliases in joins?
Answer: They make queries shorter and resolve column name ambiguity
Table aliases provide shorthand names that reduce typing and clarify which table an ambiguous column belongs to.
Which join returns only the rows that have matching values in both tables?
Answer: INNER JOIN
INNER JOIN returns only rows where the join condition is satisfied in both tables.
An EMPLOYEES table has 10 rows; a DEPARTMENTS table has 5 rows. A CROSS JOIN returns how many rows?
Answer: 50
A CROSS JOIN (Cartesian product) multiplies all rows: 10 × 5 = 50 rows.
Which keyword must follow a table name when performing an ANSI-style FULL OUTER JOIN?
Answer: FULL OUTER JOIN
The complete ANSI keyword phrase FULL OUTER JOIN specifies that all rows from both tables should be returned.
In the EMPLOYEES table, the MANAGER_ID references EMPLOYEE_ID in the same table. What type of join retrieves each employee and their manager's name?
Answer: Self-join
A self-join aliases the EMPLOYEES table twice to relate each employee row to their manager row within the same table.
What happens in an INNER JOIN when no rows satisfy the join condition?
Answer: An empty result set is returned
An INNER JOIN with no matching rows returns zero rows — it never substitutes NULLs like an outer join.