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SQL Fundamentals

Filter Rows with WHERE

Build WHERE predicates that select intended rows, handle comparison boundaries, and verify the result against included and excluded cases.

Beginner14 min read
SQL Fundamentals lessonRelational data foundationsPractice

UNTIMED COACHING

Practice before the pressure

Use feedback to correct the model, not merely memorize an option position.

GUIDED PRACTICE

Practice the lesson questions

Answer normal lesson questions without a timer. Every answer includes an explanation, and incorrect answers can be tried again before continuing.

CONCEPT MODELS

See the lesson as a system

Use these visual guides to connect the key ideas before answering the questions.

Connect the roles in Filter Rows with WHEREKeep candidate rows, filter predicate, input value, and filtered result as separate roles.
Connect the roles in Filter Rows with WHEREA topic-specific model connects four distinct roles used to reason about filter rows with where.
Table rowsTable supplies the candidate records
Filter conditionCondition tests status and priority
Input valueData matches the stored column type
Filtered resultResult keeps only matching ticket rows
Verify Predicate inspectionConnect predicate inspection with its topic-specific inspection, expected outcome, and protected database boundary.
Verify Predicate inspectionA verification model for filter rows with where connects the final data decision to its check, result, and protected boundary.
Output evidenceEvidence covers boundary and nonmatch cases
Starting checkReview output evidence
Expected resultConfirm output evidence
Safety boundaryProtect table rows scope