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.
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 plansTraining scenariosThese contextual repetitions reinforce an existing method. They preserve every historical link without pretending to be new canonical problems.Browse 118 scenarios
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.
Progress remains shared: no content is duplicated.
3 exercises are available without an account, followed by 12 more in the free Discovery space. The catalogue contains a total of 62 canonical experiences. Run a first query.