Oracle SQL Joins and Subqueries Flashcards
6 cards from real Oracle SQL practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Oracle SQL Joins and Subqueries flashcards as text
Which Oracle SQL operator checks if a subquery returns at least one row?
Answer: EXISTS
EXISTS returns TRUE if the subquery produces at least one row, and is often more efficient than IN for large datasets.
What is an inline view in Oracle SQL?
Answer: A subquery used in the FROM clause
An inline view is a subquery placed in the FROM clause, treated like a temporary table within the query.
What does a correlated subquery do in Oracle SQL?
Answer: References a column from the outer query and executes once per outer row
A correlated subquery references columns from the outer query and is re-executed for each row processed by the outer query.
Which keyword allows you to join tables using a column with the same name in both tables in Oracle SQL?
Answer: USING
The USING clause joins tables on a column that has the same name in both tables, and the column is not qualified with a table prefix in the result.
What does the NATURAL JOIN keyword do in Oracle SQL?
Answer: Joins tables based on all columns with the same name
NATURAL JOIN automatically joins tables on all columns that share the same name and data type in both tables.
Which type of subquery is used with the ANY operator in Oracle SQL?
Answer: Multi-row subquery returning multiple values
The ANY operator compares a value against each value returned by a multi-row subquery, returning TRUE if any comparison is satisfied.