Testing mode Features and test data can change before launch.
qa.cafe
BeginnerData

SQL for QA Engineers

Practice SQL in temporary browser databases. Compare supplied screen and API records with SQLite results, then write a supported defect report.

SQLiteSQLData validationJoinsTest dataDatabase investigation
Learning outcomes

What you’ll be able to do.

01

Explain tables, keys, relationships, constraints, schemas, and indexes

02

Write useful filters, joins, aggregations, and data-quality queries

03

Prepare and change test data safely with transactions

04

Compare UI and API behavior with persisted database evidence

Curriculum

9 focused modules.

34 lessons total
01Relational data and QA questionsSet up the browser workspace and connect tables, keys, and database engines to QA evidence.
  1. ↳Start SQL for QA EngineersLesson
  2. ↳What a database is and why QA caresLesson
  3. ↳Tables, rows, columns, and data typesLesson
  4. ↳Keys, relationships, and constraintsLesson
  5. ↳Database engines, schemas, and SQL dialectsLesson
02Reading evidence with SELECTAsk precise read-only questions before changing data.
  1. ↳Understanding the QA sample databaseLesson
  2. ↳Selecting columns and creating aliasesLesson
  3. ↳Removing duplicates with DISTINCTLesson
  4. ↳Sorting and limiting resultsLesson
03Filtering real application statesBuild exact SQLite predicates for Northstar Market states, boundaries, patterns, and missing values.
  1. ↳WHERE and comparison operatorsLesson
  2. ↳AND, OR, NOT, and precedenceLesson
  3. ↳IN, BETWEEN, and LIKELesson
  4. ↳NULL and three-valued logicLesson
04Shaping and inspecting dataShape Northstar Market values with SQLite functions and turn data rules into reviewable evidence.
  1. ↳Text functionsLesson
  2. ↳Numeric and date functions in SQLiteLesson
  3. ↳Conditional output with CASELesson
  4. ↳Missing, malformed, and duplicated dataLesson
05Connecting related recordsTrace related Northstar records and control join multiplication.
  1. ↳Reasoning about foreign keysLesson
  2. ↳Match related records with INNER JOINLesson
  3. ↳LEFT JOIN and missing relationshipsLesson
  4. ↳Multi-table joins and accidental duplicatesLesson
06Aggregating evidenceBuild scoped summaries, group checks, and reviewable QA measures.
  1. ↳COUNT, SUM, AVG, MIN, and MAXLesson
  2. ↳Build grouped evidence with GROUP BYLesson
  3. ↳Filtering groups with HAVINGLesson
  4. ↳Building QA metrics and duplicate checksLesson
07Preparing test data safelyCreate and change Northstar Market fixtures only in disposable memory, with scoped statements, integrity checks, and rollback.
  1. ↳Creating fixtures with INSERTLesson
  2. ↳Safe UPDATE statementsLesson
  3. ↳DELETE, constraints, and referential integrityLesson
  4. ↳Transactions, rollback, and environment safetyLesson
08QA investigationsConnect SQL evidence to product behavior and professional decisions.
  1. ↳Validating UI and API results against stored dataLesson
  2. ↳Tracing a defect across related recordsLesson
  3. ↳SQLite, other engines, indexes, and investigation habitsLesson
09SQL investigation synthesisApply every course outcome to one bounded Northstar investigation.
  1. ↳Capstone: investigate a broken order workflowLesson
  2. ↳Review your SQL evidence and choose your next practiceLesson
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