Mid-Level
October 4, 2026Spot the bug: Data Science & ML
One snippet. Find the bug, or prove there isn't one.
python
1import pandas as pd
2
3def enrich_orders_with_customer_emails(conn, orders: pd.DataFrame) -> pd.DataFrame:
4 cursor = conn.cursor()
5 emails = []
6 for _, row in orders.iterrows():
7 cursor.execute("SELECT email FROM customers WHERE id = %s", (row["customer_id"],))
8 result = cursor.fetchone()
9 emails.append(result[0] if result else None)
10 orders["email"] = emails
11 cursor.close()
12 return orders
13Click the lines that carry the problem.
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