SQL - LEFT and RIGHT JOIN
Identify the error in this query:
SELECT * FROM Customers LEFT JOIN Orders WHERE Customers.id = Orders.customer_id;
Identify the error in this query: SELECT * FROM Customers LEFT JOIN Orders WHERE Customers.id = Orders.customer_id;
medium📝 Debug Q6 of 15
Step-by-Step Solution
Solution:
Step 1: Check JOIN syntax
JOIN conditions must be specified with ON, not WHERE.Step 2: Identify misuse of WHERE
WHERE filters rows after join; join condition must be in ON clause.Final Answer:
Using WHERE instead of ON for join condition -> Option DQuick Check:
JOIN condition must use ON, not WHERE [OK]
Quick Trick: JOIN conditions go in ON clause, not WHERE [OK]
Common Mistakes:
MISTAKES- Placing join condition in WHERE clause
- Omitting ON clause entirely
- Confusing WHERE filters with join conditions
Master "LEFT and RIGHT JOIN" in SQL
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