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Concept guides/SQL/NULLs and three-valued logic

NULLs and three-valued logic

Medium5 min read

Questions it teaches

Who has no salary recordedEasy8 min Authors with no country on fileEasy8 min The average that a NULL salary ruinsMedium10 min A salary column with no blanksMedium9 min Churned accounts and whenMedium10 min Average grade, ungraded excludedMedium12 min Zero in stock is not the same as no rowHard14 min Average value per unit, without dividing by zeroHard13 min

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