What does the FROM clause do?
Interviewer Expectations for this Question
01
Core Competency
Assesses fundamental understanding of SQL & Databases conventions, runtime behavior, and memory/performance considerations.
02
Evaluation Criteria
Hiring managers look for precision, avoidance of ambiguous jargon, and ability to explain trade-offs under real production conditions.
Comprehensive Model Answer
Verified Solution
The FROM clause identifies the source table(s), views, joined tables, or subqueries from which data is to be retrieved, filtered, and aggregated.
### Logical SQL Processing Order:
In SQL execution internals, FROM is the very first clause evaluated by the database engine:
FROM(identifies source tables and evaluatesJOINoperations)WHERE(filters individual rows)GROUP BY(aggregates rows into groups)HAVING(filters aggregated groups)SELECT(projects columns and computes expressions)DISTINCT(deduplicates rows)ORDER BY(sorts output)LIMIT/OFFSET(paginates results)
Because FROM executes first, aliases defined in the FROM clause are recognized in all subsequent clauses.
Candidate Response Strategy & Interview Tips
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