Concept guides
ReadGuideTrackTopicLevelTime
DuplicatesMediumCodingSQLCodingSQLMedium5 minJoinsMediumCodingSQLCodingSQLMedium5 minAnti-joinsMediumCodingSQLCodingSQLMedium5 minNULLs and three-valued logicMediumCodingSQLCodingSQLMedium5 minDates and time bucketsMediumCodingSQLCodingSQLMedium5 minSelf-joinsHardCodingSQLCodingSQLHard4 minConditional aggregationHardCodingSQLCodingSQLHard5 minWindow functionsHardCodingSQLCodingSQLHard6 minSubqueriesHardCodingSQLCodingSQLHard6 minFunnel queriesHardCodingSQLCodingSQLHard5 minGaps and islandsHardCodingSQLCodingSQLHard5 minRecursive CTEsHardCodingSQLCodingSQLHard6 minTop N per groupHardCodingSQLCodingSQLHard5 min