NOT IN unexpectedly returns no rows
An exclusion query returns no identifiers even though some are not explicitly listed.
Explore →SARAVANA KUMAR · TECHNICAL KNOWLEDGE
Oracle SQL & PL/SQL problems & solutions
Investigate the symptom, test the likely cause and check the outcome. All scenarios are illustrative learning cases.
4 detailed problems and solutions · Illustrative learning cases
A package remains invalid after a deployment
Calls fail and recompiling the object does not restore a valid implementation.
Explore →A LEFT JOIN loses customers without paid orders
Diagnose a right-side WHERE predicate that silently removes unmatched rows.
Explore →A date filter depends on session settings
Replace implicit date conversion and midnight equality with an explicit day range.
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