SQL Joins Quiz

Which SQL JOIN returns only matching records from both tables?

• INNER JOIN

• LEFT JOIN

• RIGHT JOIN

• FULL JOIN

What does a LEFT JOIN return?

• Only matching rows from both tables

• Only rows with NULL values

• All rows from the left table and matching rows from the right table

• All rows from the right table

Which SQL JOIN returns all records from the right table?

• FULL JOIN

• INNER JOIN

• LEFT JOIN

• RIGHT JOIN

What does a FULL JOIN return?

• Only rows from the right table

• Only rows from the left table

• All rows from both tables with NULLs for non-matching rows

• Only matching rows

Which of the following is NOT a type of SQL JOIN?

• INNER JOIN

• LEFT JOIN

• CROSS JOIN

• FULL JOIN

What is the result of an INNER JOIN?

• All records from the right table

• All records from the left table

• Only records that exist in both tables

• All records from both tables

Which SQL JOIN would you use to retrieve all patients and their visit records?

• RIGHT JOIN

• LEFT JOIN

• FULL JOIN

• INNER JOIN

What happens if there is no match in a LEFT JOIN?

• Only matching records are returned

• All records are returned

• NULL values are returned for columns from the right table

• NULL values are returned for columns from the left table

Which SQL JOIN would you use to ensure all visit records are shown, even if there is no matching patient?

• INNER JOIN

• RIGHT JOIN

• LEFT JOIN

• FULL JOIN

How can multiple tables be joined in a single query?

• By using subqueries

• By using multiple JOIN clauses

• By using multiple SELECT statements

• By using UNION only