December
01
The Gift List
starterSELECT5m
24 queries · 24 days · 1 legendary December
Make December
query differently.
One handcrafted SQL challenge unlocks every day. Start with the basics, finish with the kind of query you'll want to frame. No setup. Just you, Postgres, and a blinking cursor.
24
daily challenges
~6 hrs
total practice
100%
free to join
SELECT * FROM december;
Your daily query drop
Each door reveals a fresh dataset, a focused prompt, and instant feedback. The difficulty climbs as Christmas gets closer.
starterintermediateadvanced
December
02
Naughty or Nice?
starterWHERE7m
December
03
Sort the Sleigh
starterORDER BY8m
December
04
Workshop Totals
starterAggregates10m
December
05
Elf Departments
intermediateGROUP BY12m
December
06
Missing Parcels
intermediateNULLs12m
December
07
Reindeer Roster
intermediateJOINs15m
December
08
The Late Shift
intermediateDates15m
December
09
Cookie Inventory
intermediateCASE15m
December
10
Letters to Santa
starterStrings10m
December
11
Route Optimizer
intermediateCTEs18m
December
12
Twelve Days
intermediateSubqueries18m
December
13
Toy Recall
intermediateUPDATE14m
December
14
North Pole Audit
advancedConstraints20m
December
15
Secret Santa
advancedSelf JOIN20m
December
16
Stocking Rank
advancedWindow funcs22m
December
17
Snow Day Streaks
advancedLAG / LEAD25m
December
18
Gift Hierarchy
advancedRecursive CTE25m
December
19
The Nice List
intermediateViews16m
December
20
Express Delivery
advancedIndexes22m
December
21
Workshop Queue
advancedTransactions25m
December
22
Holiday Rollup
advancedGROUPING SETS25m
December
23
Final Checks
advancedQuery plans30m
December
24
Save Christmas
advancedBoss query30m
// built for every level
Come for the streak.
Stay for the breakthrough.
New to SQL? Hints keep you moving. Already speak fluent joins? Bonus constraints and leaderboard times make every challenge worth opening.
Real Postgres
Run every query against a live, purpose-built dataset.
Build a streak
A small daily habit with visible momentum all month.
Earn the badge
Finish all 24 to unlock the limited 2026 achievement.
Don't miss day one.
Join the calendar and we'll put a fresh challenge under your terminal every morning in December.
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