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Four thick, differently coloured cables run from A through D on the left. Only one cable reaches the database on the right.

Which Cable Reaches the Database? A Sunday Puzzle

October 11, 2026
Pinal Dave
SQL Puzzle

Which cable reaches the database? Four coloured cables cross behind a rack. Follow each one to its destination.

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The backup that disappeared puzzle shows before and after shelves of six labeled cards, with one question-mark gap.

The Backup That Disappeared: Sunday Puzzle

October 4, 2026
Pinal Dave
SQL Puzzle

The backup that disappeared is one of six cards. Compare the shelves and name the missing card after another card moves.

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Two dark horizontal lines at different positions in a perspective server aisle. Compare their lengths before reading the answer.

The Longer Query: A Sunday SQL Illusion

September 27, 2026
Pinal Dave
SQL Puzzle

The longer query seems obvious in this Sunday illusion. Compare two bars in a server aisle, then check your answer.

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sql puzzle

SQL Puzzle – Retrieve the Unique Evens Under 10

November 21, 2023
Pinal Dave
SQL Puzzle
SQL Distinct

In that spirit, let me walk through a bite-sized SQL puzzle that helps reinforce some key concepts. Let us see Retrieve the Unique Evens Under 10 puzzle.

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The Flight Connection Puzzle

SQL SERVER – The Flight Connection Puzzle

July 31, 2023
Pinal Dave
SQL Puzzle
CTE, SQL Server

Today we are going to see another such puzzle – The Flight Connection Puzzle. This blog post is going to be really fun blog post.

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The Two Doors, Two Guards Puzzle

SQL SERVER – The Two Doors, Two Guards Puzzle

July 28, 2023
Pinal Dave
SQL Puzzle
SQL Scripts

I came across a puzzle about “The Two Doors, Two Guards,” popularly known as the “Two Doors Riddle” or the “Heaven and Hell Riddle”.

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Unmatched guide channels are inspected beside an empty receiving recess.

SQL Puzzle – Unsolved CASE Expression

April 20, 2021
Pinal Dave
SQL Puzzle
SQL CASE, SQL Scripts, SQL Server

This Unsolved CASE puzzle asks you to predict its result before execution. The preceding bitwise challenge drew more than 125 responses.

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