Count completed orders and reconcile sales
SQL practice · Retail case · 15–20 minutes. Start with retail-setup.sql in a disposable local SQLite database.
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SQL practice · Retail case · 15–20 minutes. Start with retail-setup.sql in a disposable local SQLite database.
Explore & practiseCalculate channel share with a common denominator
SQL practice · Retail case · 15–20 minutes. Start with retail-setup.sql in a disposable local SQLite database.
Explore & practiseFind average order value at order grain
SQL practice · Retail case · 15–20 minutes. Start with retail-setup.sql in a disposable local SQLite database.
Explore & practiseRank completed orders reproducibly
SQL practice · Retail case · 15–20 minutes. Start with retail-setup.sql in a disposable local SQLite database.
Explore & practiseKeep excluded records visible
SQL practice · Retail case · 15–20 minutes. Start with retail-setup.sql in a disposable local SQLite database.
Explore & practiseUse SUMIFS with an explicit status
Excel practice · Use the supplied CSV with headers in row 1. Formulas use English function names and commas; your locale may use translated names or semicolons.
Explore & practiseCount completed Web orders
Excel practice · Use the supplied CSV with headers in row 1. Formulas use English function names and commas; your locale may use translated names or semicolons.
Explore & practiseBuild a reconciled PivotTable
Excel practice · Use the supplied CSV with headers in row 1. Formulas use English function names and commas; your locale may use translated names or semicolons.
Explore & practiseCalculate growth without confusing percentage points
Excel practice · Use the supplied CSV with headers in row 1. Formulas use English function names and commas; your locale may use translated names or semicolons.
Explore & practiseReconcile inventory counts
Excel practice · Use the supplied CSV with headers in row 1. Formulas use English function names and commas; your locale may use translated names or semicolons.
Explore & practiseCalculate the overall conversion rate
Excel practice · Use the supplied CSV with headers in row 1. Formulas use English function names and commas; your locale may use translated names or semicolons.
Explore & practiseRead and validate an order file
Python practice · Python 3.10+ standard library · Run locally in a folder containing the supplied files.
Explore & practiseFilter and sum integer money
Python practice · Python 3.10+ standard library · Run locally in a folder containing the supplied files.
Explore & practiseGroup sales by month in Python
Python practice · Python 3.10+ standard library · Run locally in a folder containing the supplied files.
Explore & practiseDetect duplicate IDs without deleting evidence
Python practice · Python 3.10+ standard library · Run locally in a folder containing the supplied files.
Explore & practiseCreate a reproducibility fingerprint
Python practice · Python 3.10+ standard library · Run locally in a folder containing the supplied files.
Explore & practiseHandle a zero denominator explicitly
Python practice · Python 3.10+ standard library · Run locally in a folder containing the supplied files.
Explore & practiseResolve a missing value using evidence
Data preparation practice · Use the messy source and independent clean control. Corrections belong in a derived output and a change log.
Explore & practiseNormalize a category without losing the source
Data preparation practice · Use the messy source and independent clean control. Corrections belong in a derived output and a change log.
Explore & practiseSeparate repeated exports from conflicting records
Data preparation practice · Use the messy source and independent clean control. Corrections belong in a derived output and a change log.
Explore & practiseDeclare the row meaning before cleaning
Data preparation practice · Use the messy source and independent clean control. Corrections belong in a derived output and a change log.
Explore & practiseProtect cents and identifiers during import
Data preparation practice · Use the messy source and independent clean control. Corrections belong in a derived output and a change log.
Explore & practiseProduce a complete correction log
Data preparation practice · Use the messy source and independent clean control. Corrections belong in a derived output and a change log.
Explore & practiseChoose a defensible sales chart
Visualization practice · A useful chart makes its units, population and limitations inspectable.
Explore & practiseShow counts beside conversion rates
Visualization practice · A useful chart makes its units, population and limitations inspectable.
Explore & practiseExplain chart meaning without color alone
Visualization practice · A useful chart makes its units, population and limitations inspectable.
Explore & practisePresent an inventory exception honestly
Visualization practice · A useful chart makes its units, population and limitations inspectable.
Explore & practiseWrite a precise comparison headline
Visualization practice · A useful chart makes its units, population and limitations inspectable.
Explore & practiseDesign a decision-focused reporting page
Visualization practice · A useful chart makes its units, population and limitations inspectable.
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