Customer Placing the Largest Number of Orders
A easy-tier problem at 64% community acceptance, tagged with Database. Reported in interviews at X and 0 others.
You've got a database problem on the docket, and it's the kind that sounds simple until you realize the gotcha. X asks this one. You're handed a table of orders, maybe with customer IDs and timestamps or amounts, and you need to surface the single customer who placed the most orders. Sixty-four percent of candidates pass it, which means forty percent trip on the join, the aggregation, or the tie-breaking logic. If you blank on how to structure the query during the OA, StealthCoder solves it invisibly in seconds and moves you past the stall.
Companies that ask "Customer Placing the Largest Number of Orders"
Customer Placing the Largest Number of Orders is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Built by an engineer who got tired of watching his cohort grind for six months and still get filtered at the OA stage.
Get StealthCoderThe trap here is almost always the same: candidates write a query that works for the happy path but fails when there's a tie. You need GROUP BY to count orders per customer, ORDER BY to sort by that count descending, and then a LIMIT 1 to grab the winner. But what if two customers have the same order count. Does the problem want any one of them, or the one with the smallest ID, or something else. Read the spec carefully. You'll also see candidates forget to handle nulls or write subqueries when a simple window function or TOP 1 clause would run faster. Database problems test whether you think like the interviewer. StealthCoder gives you a working solution the instant you need it, so you don't lose momentum on the live assessment.
Pattern tags
You know the problem.
Make sure you actually pass it.
Customer Placing the Largest Number of Orders recycles across companies for a reason. It's easy-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Built by an engineer who got tired of watching his cohort grind for six months and still get filtered at the OA stage. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Customer Placing the Largest Number of Orders interview FAQ
Is this problem still asked at top companies?+
X reports it. It's a database fundamentals check, not a rare edge case. If you see a database problem in the loop, this pattern (aggregate, sort, limit) will show up somewhere. Master it once, reuse it across multiple problems.
What's the actual trick to solving this?+
GROUP BY customer_id, COUNT(*) to tally orders, then ORDER BY count DESC and LIMIT 1. The gotcha is handling ties. Read whether the problem wants any customer or a specific tie-breaker like min(customer_id). That detail changes the query.
Should I use a subquery or a window function?+
Subquery with MAX(count) in a HAVING clause works. Window functions (RANK or ROW_NUMBER over ORDER BY count DESC) are faster for large datasets but add complexity. For an easy problem, a clean subquery is safest and most readable.
How does this relate to other database problems?+
This is the template for any 'find the top X by metric' question. Once you nail GROUP BY and ORDER BY LIMIT, you'll recognize the pattern in problems about top-earning employees, most-viewed products, and busiest hours.
Why do people fail this if it's marked easy?+
Forgetting LIMIT 1, mishandling ties, or writing an inefficient nested subquery without proper indexing. Also, some write the query correctly but return the wrong column (e.g., count instead of customer_id). Test your output shape before submitting.
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