SQL for Business Analysis

Learn how the course schema fits together, then select, filter, sort and categorise rows with SELECT, WHERE, ORDER BY, LIMIT and CASE WHEN.

1. Tables, rows and keysHow relational tables are organised, what primary and foreign keys guarantee, and why you should name the grain of every table before you query it.15 min · free preview · worked example · exercise
2. SELECT, WHERE, ORDER BY and LIMITChoose columns, filter rows precisely, sort the result and limit the output, avoiding the AND/OR and date-range traps.18 min · worked example · exercise
3. Calculated columns and CASE WHENCreate new columns with arithmetic and conditions, and use CASE WHEN to sort rows into business categories you define.16 min · worked example · exercise
4. Module quiz4 questions with explanations

Summarise rows with aggregates, GROUP BY and HAVING, handle missing values deliberately, and group activity by month in different databases.

1. Aggregates, GROUP BY and HAVINGCount, sum and average rows, group them into categories, and filter groups with HAVING instead of WHERE.20 min · worked example · exercise
2. NULLs and missing valuesWhat NULL means, why it breaks ordinary comparisons, and how IS NULL, COALESCE and aggregates treat missing values.18 min · worked example · exercise
3. Working with dates and monthsGroup activity by month, calculate date differences, and handle the syntax differences between databases.20 min · worked example · exercise
4. Module quiz4 questions with explanations

Combine tables with INNER and LEFT joins, understand why joins change row counts and duplicate values, and structure longer queries with CTEs.

1. INNER JOIN: combining related tablesJoin tables on their keys, use aliases, and understand which rows an inner join keeps and which it drops.18 min · worked example · exercise
2. LEFT JOIN, row counts and duplicate fan-outKeep unmatched rows with LEFT JOIN, avoid turning it back into an inner join, and recognise when a join multiplies rows and inflates totals.22 min · worked example · exercise
3. CTEs and readable SQLBreak long queries into named steps with WITH, pre-aggregate safely, and format SQL so that colleagues can review it.20 min · worked example · exercise
4. Module quiz4 questions with explanations

Rank, accumulate and compare periods with window functions, build the standard business queries, and check results before anyone acts on them.

1. Window functions: ROW_NUMBER, running totals and LAGCalculate rankings, running totals and period-over-period changes without collapsing rows, using OVER with PARTITION BY and ORDER BY.24 min · worked example · exercise
2. Core business queries: revenue, top customers, cohorts and funnelsPatterns for four of the queries analysts are asked for most often: revenue by month, top customers, retention cohorts and funnel conversion.25 min · worked example · exercise
3. Checking results, read-only access and data privacyVerify a result with row counts, spot checks and reconciliation before sharing it, and work safely with live systems and personal data.20 min · worked example · exercise
4. Module quiz4 questions with explanations