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Metricwise

Metricwise Academy · SQL

Learn SQL with interactive exercises.

Read databases, write queries, and find the answers hidden in your tables.

  • Beginner friendly
  • 11 modules
  • 63 lessons
  • Practice in your browser
Start learning for freeView curriculum

Three preview lessons, no account needed. Starter includes free modules after sign-in; Pro, Team, and Enterprise include the full course. Compare access.

Lesson preview What is SQL?

Return every customer column and sort by customer_id.

SELECT *
FROM customers
ORDER BY customer_id;
customer_idnameregion
1AlexNorth
2SamSouth
3RobinNorth
4DrewWest
5KaiEast

Query result · The source table stays unchanged.

What you will learn

Learn how tables become answers. Start by reading a database structure and selecting columns, then progress to filtering, grouping, joins, and queries that are easier to understand and check.

  • Read columns, data types, and keys in a table.
  • Select and filter the records that answer a question.
  • Group and summarize data with a clear population.
  • Join tables while paying attention to duplicated rows.

Before you begin

You do not need previous SQL experience or your own database. The course provides the exercise data. Familiarity with rows and columns is useful, but the first lessons explain the foundations.

Put it into practice

Use SQL to pull a focused customer list, summarize orders by category, or investigate a change in activity. Understanding the shape of a table helps you choose a query that answers the business question accurately.

Inside the free preview

The first lessons introduce SQL, help you read columns, types, and keys, and ask you to select the columns you need. Write and run a query against the provided data, then use the feedback to refine your answer.

Your learning path

The first three lessons are open to everyone. Sign in for Starter modules; full course access is included with Pro, Team, and Enterprise.

01Read a database6 lessons

Understand table structure and retrieve a predictable set of rows.

  1. What is SQL?Free preview
  2. Read columns, types, and keysFree preview
  3. Select the columns you needFree preview
  4. Name calculated columnsSign in
  5. Return distinct valuesSign in
  6. Sort and limit deliberatelySign in
02Filter and classify7 lessons

Translate business conditions into precise row tests.

  1. Filter with WHERESign in
  2. Combine AND, OR, and NOTSign in
  3. Use IN and BETWEENSign in
  4. Match text with LIKESign in
  5. Understand NULLSign in
  6. Replace missing labels with COALESCESign in
  7. Classify with CASESign in
03Summarise records6 lessons

Calculate trustworthy totals with explicit populations and grouping.

  1. Count rows and non-NULL valuesSign in
  2. Calculate SUM and AVGSign in
  3. Find MIN and MAXSign in
  4. Group records with GROUP BYSign in
  5. Filter groups with HAVINGSign in
  6. Build conditional metricsSign in
04Join without double-counting6 lessons

Combine tables while preserving the intended result grain.

  1. Join related recordsSign in
  2. Keep unmatched records with LEFT JOINSign in
  3. Use EXISTS and NOT EXISTSSign in
  4. See one-to-many fanoutSign in
  5. Pre-aggregate before joiningSign in
  6. Understand RIGHT, FULL, and CROSS joinsSign in
05Compose clear queries5 lessons

Use reusable query stages, compatible set operations, and explicit time boundaries.

  1. Use a scalar subquerySign in
  2. Name a stage with a CTESign in
  3. Combine rows with UNION ALLSign in
  4. Filter a complete date periodSign in
  5. Clean text and cast typesSign in
06Analyse with window functions5 lessons

Compare rows without collapsing them into grouped summaries.

  1. Add a total without losing rowsSign in
  2. Assign row numbers and ranksSign in
  3. Calculate a running totalSign in
  4. Compare with the previous row using LAGSign in
  5. Choose the latest record per keySign in
07Work with PostgreSQL7 lessons

Practise typed queries and controlled changes in an operational database sandbox.

  1. Use PostgreSQL names, casts, and datesSign in
  2. Insert a new rowSign in
  3. Update and delete selected rowsSign in
  4. Use transactions and rollbackSign in
  5. Enforce data rules and bind parametersSign in
  6. Inspect a query planSign in
  7. Expand PostgreSQL JSONBSign in
08Work with BigQuery6 lessons

Use GoogleSQL and understand analytical warehouse query behaviour.

  1. Name BigQuery tables and jobsSign in
  2. Use BigQuery dates and time zonesSign in
  3. Handle bad inputs with SAFE functionsSign in
  4. Filter windows with QUALIFYSign in
  5. Expand ARRAY and STRUCT with UNNESTSign in
  6. Plan warehouse work and check qualitySign in
09Project: PostgreSQL order operations6 lessons

Build a small operational workflow with reconciled reports and controlled stock changes.

  1. Project brief and source checksSign in
  2. Build a product revenue reportSign in
  3. Reserve stock and create an orderSign in
  4. Make a key-based update repeatableSign in
  5. Inspect access and parameterise a reportSign in
  6. Publish a reconciled operational summarySign in
10Project: BigQuery event warehouse6 lessons

Build deduplicated daily metrics and compare the warehouse workflow with PostgreSQL.

  1. Scope the warehouse projectSign in
  2. Deduplicate replayed eventsSign in
  3. Reconcile nested product revenueSign in
  4. Build daily warehouse metricsSign in
  5. Make a daily load repeatable with MERGESign in
  6. Compare dialects and hand over the reportSign in
11Project: cross-dialect sales reconciliation3 lessons

Port one reporting contract and reconcile PostgreSQL and BigQuery outputs.

  1. Project: establish the PostgreSQL baselineSign in
  2. Project: port the contract to BigQuerySign in
  3. Project: reconcile and release the reportSign in

Questions, answered

SQL course questions

Do I need to connect a database?
No. The interactive exercises include their own datasets and run in the browser preview. You can concentrate on the query without setting up a database server.
What comes after the introductory lessons?
The curriculum continues into filtering, summaries, joins, query composition, and window functions. Sign in after the three preview lessons to continue; Starter includes free modules, while Pro, Team, and Enterprise include full Academy access.
How do I continue after the preview?
Sign in from the lesson gate to carry your preview progress into the app on the same browser and device. Your local draft stays available while you complete sign-in. Starter includes free Academy modules; Pro, Team, and Enterprise include full Academy access.
Can I return to a lesson?
Yes. Use the curriculum to revisit a preview lesson and practice again. Progress is kept in your browser when local storage is available; clearing site data can remove that local copy.

Start with one lesson

A little practice goes a long way.

Open what is sql? and try the exercises at your own pace.

Start learning for free

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