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Beginner · 15 min · SELECTStart →Interactive SQL exercises
Solved SQL exercises: practise from beginner to advanced
Practise SQL online through progressive business cases. Each exercise provides fictional data, hints, result validation and an explained solution.
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Data Analyst
Practise with metrics, customers and sales.
SQL · KPI · analyse métierExplore the path →Interview preparation
Train with timed, explained question sets.
30 défis · 3 niveauxStart →More filters
62 exercises shown
UNION ALLSQL Essentials
Keep origin with UNION ALL
Stack two lists without losing traceability.
Level : IntermediateCompare plansINTERSECTSQL Essentials
Find the intersection of two lists
Keep only the values present in both sets.
Level : IntermediateCompare plansSELF JOINSQL Essentials
Connect a table to itself
Represent a simple hierarchy with two aliases.
Level : IntermediateCompare plansJOIN · GROUP BYSQL Essentials
Calculate revenue using three tables
Follow the keys without adding a measure twice.
Level : IntermediateCompare plansCASE WHENSQL Essentials
Classify inventory risk
Transform operational thresholds into readable categories.
Level : IntermediateCompare plansNULL · COUNTSQL Essentials
Measure phone completeness
Produce a quality rate from explicit volumes.
Level : IntermediateCompare plansQuality · HAVINGSQL Essentials
Detect duplicate emails
Transform a uniqueness constraint into measurable control.
Level : IntermediateCompare plansQuality · SubqueriesSQL Essentials
Reconcile orders and payments
Compare two independent totals in a single control line.
Level : IntermediateCompare plansCTE · CalculationsSQL Essentials
Calculate the overall margin with a CTE
Separate basic measurements and derived indicators.
Level : IntermediateCompare plansCTE · TOP NSQL Essentials
Rank the top three categories
Prepare a reliable aggregate before limiting the ranking.
Level : IntermediateCompare plansCASE · AggregationsSQL Essentials
Calculate multiple statuses in one line
Build conditional indicators without multiplying queries.
Level : IntermediateCompare plansAVG · HAVINGSQL Essentials
Filter an average basket with HAVING
Apply a threshold on an aggregated indicator.
Level : IntermediateCompare plansMIN · GROUP BYSQL Essentials
Find the first order
Bring back a history to its first date per customer.
Level : IntermediateCompare plansCTE · Auto-joinSQL Essentials
Compare each month to the previous one
Align two periods to calculate an absolute evolution.
Level : IntermediateCompare plansProject · joinsSQL Essentials
Calculate margin by category
Distinguish between revenue, cost and margin on paid lines.
Level : IntermediateCompare plansProject · KPISQL Essentials
Track monthly payment rate
Combine timing and conditional aggregation into one monitorable indicator.
Level : IntermediateCompare plansWHERE · ORDER BYNo account
Filter then sort a threshold
Keep the threshold inclusive and make the outcome controllable.
Level : BeginnerOpen exerciseIN · ORDER BYDiscovery
Select multiple brands
Express a closed list without repeating multiple OR.
Level : BeginnerCreate a free accountExpressions · AliasesDiscovery
Calculate a unit margin
Create a simple indicator from two compatible columns.
Level : BeginnerCreate a free accountText · LENGTHDiscovery
Control the length of names
Measure text before exporting to a limited size.
Level : BeginnerCreate a free accountlevel of detail · joins · AggregationsSQL Analyst
Avoid double counting after several joins
Calculate customer revenue without multiplying lines when an order has multiple items and multiple payments.
Level : AdvancedCompare plansCohorts · Retention · DatesSQL Analyst
Building a cohort and measuring retention
Go from raw events to a retention matrix without double-counting an active account.
Level : AdvancedCompare plansRFM · Segmentation · CASESQL Analyst
Build a complete RFM segmentation
Measure recency, frequency, and value, then turn scores into actionable segments.
Level : AdvancedCompare plansFunnel · Conversion · FILTERSQL Analyst
Measure a funnel without counting duplicate events
Transform an imperfect event log into conversion rates by stage and channel.
Level : AdvancedCompare plansAdditional business situationsThese exercises reuse an existing method in a new context to strengthen your reflexes.Browse 118 situations
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118 exercises shown
WHERE · ORDER BYSQL Essentials
Isolate actually paid transactions — a regional bookstore · training scenario
Isolate the actually paid operations in the context of a regional bookstore, with a controllable result. You must produce the result, check it on the source data and explain what it allows you to decide in this network of bookstores.
Level : BeginnerCompare plansGROUP BY · SUMSQL Essentials
Compare value by city — a regional bookstore · training scenario
Compare the value by city in the context of a regional bookstore, with a controllable result. You must produce the result, check it on the source data and explain what it allows you to decide in this network of bookstores.
Level : BeginnerCompare plansCASESQL Essentials
Prioritize amounts — a regional bookstore · training scenario
Prioritize amounts in the context of a regional bookstore, with a controllable result. You must produce the result, check it on the source data and explain what it allows you to decide in this network of bookstores.
Level : BeginnerCompare plansCOUNT · GROUP BYSQL Essentials
Count volume by status — a regional bookstore · training scenario
Count volume by status in the context of a regional bookstore, with a controllable result. You must produce the result, check it on the source data and explain what it allows you to decide in this network of bookstores.
Level : BeginnerCompare plansDISTINCTSQL Essentials
List active categories — a regional bookstore · training scenario
List active categories in the context of a regional bookstore, with a controllable result. You must produce the result, check it on the source data and explain what it allows you to decide in this network of bookstores.
Level : BeginnerCompare plansDATE_TRUNC · SUMSQL Essentials
Follow monthly progress — a regional bookstore · training scenario
Monitor monthly developments in the context of a regional bookstore, with a controllable result. You must produce the result, check it on the source data and explain what it allows you to decide in this network of bookstores.
Level : BeginnerCompare plansWHERE · ORDER BYSQL Essentials
Isolating actually paid operations — a network of clinics · training scenario
Isolate actually paid operations in the context of a network of clinics, with a controllable result. You must produce the result, check it on the source data and explain what it allows you to decide in this network of clinics.
Level : BeginnerCompare plansGROUP BY · SUMSQL Essentials
Compare value by city — a network of clinics · training scenario
Compare the value by city in the context of a network of clinics, with a controllable result. You must produce the result, check it on the source data and explain what it allows you to decide in this network of clinics.
Level : BeginnerCompare plansCASESQL Essentials
Prioritize amounts — a network of clinics · training scenario
Prioritize amounts in the context of a network of clinics, with a controllable outcome. You must produce the result, check it on the source data and explain what it allows you to decide in this network of clinics.
Level : BeginnerCompare plansCOUNT · GROUP BYSQL Essentials
Count volume by status — a network of clinics · training scenario
Count volume by status in the context of a network of clinics, with a controllable result. You must produce the result, check it on the source data and explain what it allows you to decide in this network of clinics.
Level : BeginnerCompare plansDISTINCTSQL Essentials
List active categories — a network of clinics · training scenario
List active categories in the context of a network of clinics, with a controllable result. You must produce the result, check it on the source data and explain what it allows you to decide in this network of clinics.
Level : BeginnerCompare plansDATE_TRUNC · SUMSQL Essentials
Monitor monthly progress — a network of clinics · training scenario
Monitor monthly developments in the context of a network of clinics, with a controllable result. You must produce the result, check it on the source data and explain what it allows you to decide in this network of clinics.
Level : BeginnerCompare plansWHERE · ORDER BYSQL Essentials
Isolating actually paid transactions — a training organization · training scenario
Isolate the operations actually paid in the context of a training organization, with a controllable result. You must produce the result, check it on the source data and explain what it allows to decide in this training organization.
Level : BeginnerCompare plansGROUP BY · SUMSQL Essentials
Compare value by city — a training organization · training scenario
Compare the value per city in the context of a training organization, with a controllable result. You must produce the result, check it on the source data and explain what it allows to decide in this training organization.
Level : BeginnerCompare plansCASESQL Essentials
Prioritize amounts — a training organization · training scenario
Prioritize amounts in the context of a training organization, with a controllable result. You must produce the result, check it on the source data and explain what it allows to decide in this training organization.
Level : BeginnerCompare plansCOUNT · GROUP BYSQL Essentials
Count volume by status — a training organization · training scenario
Count the volume by status in the context of a training organization, with a controllable result. You must produce the result, check it on the source data and explain what it allows to decide in this training organization.
Level : BeginnerCompare plansDISTINCTSQL Essentials
List active categories — a training organization · training scenario
List active categories in the context of a training organization, with a controllable result. You must produce the result, check it on the source data and explain what it allows to decide in this training organization.
Level : BeginnerCompare plansDATE_TRUNC · SUMSQL Essentials
Monitor monthly progress — a training organization · training scenario
Monitor monthly progress in the context of a training organization, with a controllable result. You must produce the result, check it on the source data and explain what it allows to decide in this training organization.
Level : BeginnerCompare plansWHERE · ORDER BYSQL Essentials
Isolate actual paid transactions — a delivery company · training scenario
Isolate actual paid operations in the context of a delivery business, with a controllable outcome. You must produce the result, check it on the source data and explain what it allows you to decide in this delivery company.
Level : BeginnerCompare plansGROUP BY · SUMSQL Essentials
Compare value by city — a delivery company · training scenario
Compare the value by city in the context of a delivery company, with a controllable result. You must produce the result, check it on the source data and explain what it allows you to decide in this delivery company.
Level : BeginnerCompare plansCASESQL Essentials
Prioritize amounts — a delivery company · training scenario
Prioritize amounts in the context of a delivery business, with a controllable outcome. You must produce the result, check it on the source data and explain what it allows you to decide in this delivery company.
Level : BeginnerCompare plansCOUNT · GROUP BYSQL Essentials
Count volume by status — a delivery company · training scenario
Count volume by status in the context of a delivery business, with a controllable result. You must produce the result, check it on the source data and explain what it allows you to decide in this delivery company.
Level : BeginnerCompare plansDISTINCTSQL Essentials
List active categories — a delivery company · training scenario
List active categories in the context of a delivery business, with a controllable result. You must produce the result, check it on the source data and explain what it allows you to decide in this delivery company.
Level : BeginnerCompare plansDATE_TRUNC · SUMSQL Essentials
Monitor monthly progress — a delivery company · training scenario
Monitor monthly progress in the context of a delivery company, with a controllable result. You must produce the result, check it on the source data and explain what it allows you to decide in this delivery company.
Level : BeginnerCompare plansTwo focused paths reuse these experiences.
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