Learning SQL Basics: Comparison, Logical, and NULL Operators in PostgreSQL

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A learner shares what they practiced over several days with SQL basics using PostgreSQL and the DBeaver tool. The walkthrough uses queries from their own assignment on a patients table containing fields such as name, gender, age, county, and admission date. It covers comparison operators, logical operators like AND, OR, and NOT with a note on evaluation order, and the IN and BETWEEN filters for lists and ranges. The author also explains that NULL denotes a missing or unknown value, not zero or an empty string, and shows how to detect it with IS NULL. The piece closes by encouraging beginners to experiment with a small table to learn from mistakes.

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TryHackMe Billing Room: Exploiting MagnusBilling Command Injection and fail2ban Escalation

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ProgrammingDEV Community ·

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ProgrammingDEV Community ·

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ProgrammingDEV Community ·

Teams Split AI Agents Into Specialized Roles Under an Orchestrator

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