[Solved] A query joining orders and products is slow. The query is:SELECT * FROM orders JOIN products ON orders.prod_id = products.... What join order change might improve performance? | SQL

SQL - Advanced Joins

A query joining orders and products is slow. The query is:
SELECT * FROM orders JOIN products ON orders.prod_id = products.id;
Indexes exist on both tables. What join order change might improve performance?

ARemove the join condition

BAdd a WHERE clause filtering orders

CRewrite to join products first, then orders

DUse a CROSS JOIN instead

Step-by-Step Solution

Solution:

Step 1: Consider join order effect
Joining the smaller or more selective table first can reduce rows early and improve speed.
Step 2: Apply to given tables
If products is smaller or more selective, joining it first can improve performance.
Final Answer:
Rewrite to join products first, then orders -> Option C
Quick Check:
Changing join order can improve speed [OK]

Quick Trick: Join smaller or selective tables first to speed queries [OK]

Common Mistakes:

MISTAKES

Removing join condition causes wrong results
Using CROSS JOIN increases rows, slowing query
Assuming WHERE clause fixes join order issues

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A query joining orders and products is slow. The query is:

Step 1: Consider join order effect

Step 2: Apply to given tables

Final Answer:

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