INTERACTIVE LECTURES
Develop and defend an analysis
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Separate a clear query from a fast query
Step 2 of 3 · Database: Pixar & Box Office
READ & UNDERSTAND
An index can help locate rows but also consumes space and adds maintenance work when data changes. A faster claim requires measurement on the relevant workload.
EXPLAIN QUERY PLAN describes a strategy; it is not a timing result. Tiny classroom datasets are useful for learning plans, but do not establish production-scale performance.
A view saves a query definition for reuse, not a frozen result snapshot. Triggers run on configured changes and need explicit tests for their side effects. Practice creating views, indexes, and triggers in a disposable desktop database before applying them elsewhere.
Worked example
SELECT id, title FROM movies WHERE year >= 2000 ORDER BY id;
The filter includes the boundary year 2000. The final id ordering is part of this output contract and must be retained when comparing an equivalent rewrite.
Run EXPLAIN QUERY PLAN followed by this SELECT to inspect the chosen strategy. It does not measure elapsed time or prove that an index would improve a larger workload.
Your question
Return id and title for movies released in or after 2000, ordered by id. Then inspect its plan separately using EXPLAIN QUERY PLAN.
Explain your evidence
What evidence would justify calling one equivalent query faster? What does timing a 14-row fixture fail to establish?
Try a query to unlock the worked-answer discussion.
Query results
Predict the result, then run your query.Predict the result, then run your query.
Read-only activity · One statement per run · First 200 rows displayed · Checks compare the complete bounded result, not just this preview.
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