Questena practice
SQL: NULL, Joins and Aggregates
Three-valued logic, outer joins and aggregate behaviour, as defined by PostgreSQL 18.
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Scored practice set
Complete a fixed vocabulary or subject practice set with answers shown at the end. It is not an exam simulation.
Questions: 25 · editorial practice threshold: 18
Topics
4 sections · 25 questions- NULL and three-valued logic8 q
- Joins7 q
- Aggregates and grouping6 q
- Constraints and uniqueness4 q