Pattern
Deduplication
15 problemsin this pattern, climbing easy → medium → hard. Pick wherever you're calibrated.
EZ
0 / 5 solvedEasy
MD
0 / 6 solvedMedium
- NEWKeep earliest event per (user, event_type)SQL · ~7 min
- NEWRemove fully-duplicate rowsSQL · ~5 min
- NEWMerge dupes by latest non-null per columnSQL · ~12 min
- NEWKeep each customer's earliest versionSQL · ~8 min
- NEWKeep the most complete row per customerSQL · ~10 min
- NEWDeduplicate keeping the latest record per idPython · ~11 min
HD
0 / 4 solved