[Solved] Consider the tables members(id) and subscriptions(member_id). What will this query return?SELECT m.id FROM members m LEFT JOIN subscriptions s ON m.id = s.member_id WHERE s.... | SQL

SQL - LEFT and RIGHT JOIN

Consider the tables members(id) and subscriptions(member_id). What will this query return?

SELECT m.id FROM members m LEFT JOIN subscriptions s ON m.id = s.member_id WHERE s.member_id IS NULL;

Assuming members has 6 rows and subscriptions has 4 rows linked to 4 different members.

AIDs of subscriptions without matching members

BIDs of members who have at least one subscription

CAll member IDs regardless of subscription status

DIDs of members who do not have any subscription

Step-by-Step Solution

Solution:

Step 1: LEFT JOIN behavior
The query joins all members with their subscriptions, if any.
Step 2: WHERE s.member_id IS NULL
This filters to only members without matching subscriptions.
Step 3: Result count
Since 4 members have subscriptions, 6 - 4 = 2 members will be returned.
Final Answer:
IDs of members who do not have any subscription -> Option D
Quick Check:
LEFT JOIN + NULL filter returns unmatched left rows [OK]

Quick Trick: NULL in right table column means no match found [OK]

Common Mistakes:

MISTAKES

Master "LEFT and RIGHT JOIN" in SQL

9 interactive learning modes - each teaches the same concept differently

More SQL Quizzes

Consider the tables members(id) and subscriptions(member_id). What will this query return?