SELECTNo account
Select the correct columns
Show only the name and price of each product.
Level : BeginnerOpen exerciseGuided practice
Understand the need. Write the query. Defend your result.
Every exercise combines a business context, an approach, hints, a SQL environment, detailed feedback and an extra challenge.
44 exercises shown
WHERE · ORDER BYNo account
Filter and sort orders
Find orders over 50 TND, from highest to lowest.
Level : BeginnerOpen exerciseINNER JOINSQL Essentials
Connect customers and orders
Associate each order with the name of the customer who placed it.
Level : IntermediateView SQL EssentialsDISTINCT · LIMITDiscovery space
List unique categories
Display the first three unique categories in alphabetical order.
Level : BeginnerCreate a free accountNULL · COALESCEDiscovery space
Replace a NULL value with COALESCE
Display clear labeling when a customer’s phone is absent.
Level : BeginnerCreate a free accountCOUNT · SUM · AVGSQL Essentials
Calculate paid order indicators
Calculate the volume, total and average over a specific area.
Level : BeginnerView SQL EssentialsGROUP BY · HAVINGSQL Essentials
Group revenue by category
Calculate totals by category and keep only the most important ones.
Level : BeginnerView SQL EssentialsLEFT JOIN · COUNTSQL Essentials
Keep customers without orders
Count the orders of each customer without excluding new registrants.
Level : BeginnerView SQL EssentialsCTE · CASESQL Essentials
Segment customers with a CTE
Calculate the total per customer, then transform this result into a business segment.
Level : IntermediateView SQL EssentialsBETWEENDiscovery space
Filter a price range
Select an inclusive interval and check its limits.
Level : BeginnerCreate a free accountINDiscovery space
Filter multiple statuses
Replace multiple OR with a readable business list.
Level : BeginnerCreate a free accountLIKEDiscovery space
Search for a prefix with LIKE
Use a simple text pattern without confusing prefix and content.
Level : BeginnerCreate a free accountIS NULLDiscovery space
Identify missing deliveries
Distinguish a missing date from an empty string or status.
Level : BeginnerCreate a free accountExpressions · ROUNDDiscovery space
Calculate a price including tax
Transform a source price with a precise formula and alias.
Level : BeginnerCreate a free accountText · ConcatenationDiscovery space
Assemble a product label
Create a readable label from two columns.
Level : BeginnerCreate a free accountTRIM · UPPER · DISTINCTDiscovery space
Normalize a list of cities
Create a clean dimension before counting customers.
Level : BeginnerCreate a free accountDates · EXTRACTSQL Essentials
Extract the year of registration
Derive a calendar component without transforming the scope.
Level : BeginnerView SQL EssentialsDates · GROUP BYSQL Essentials
Calculate monthly revenue
Group together several channels over the same monthly period.
Level : IntermediateView SQL EssentialsDates · WHERESQL Essentials
Analyze a quarter with limits
Filter a complete period with an exclusive upper bound.
Level : IntermediateView SQL EssentialsLEFT JOIN · HAVINGSQL Essentials
Find customers without orders
Keep the starting population and isolate the absence of activity.
Level : IntermediateView SQL EssentialsEXISTSSQL Essentials
Test for the existence of a large order
Filter a population without duplicating it by its history.
Level : IntermediateView SQL EssentialsJOIN · AVGSQL Essentials
Calculate the average basket per customer
Only aggregate orders that are actually paid.
Level : IntermediateView SQL EssentialsSubquery · AVGSQL Essentials
Compare to average price
Use an aggregated value as a dynamic threshold.
Level : IntermediateView SQL EssentialsUNIONSQL Essentials
Merge customers and prospects
Create a single list from two compatible sources.
Level : IntermediateView SQL EssentialsUNION ALLSQL Essentials
Keep origin with UNION ALL
Stack two lists without losing traceability.
Level : IntermediateView SQL EssentialsINTERSECTSQL Essentials
Find the intersection of two lists
Keep only the values present in both sets.
Level : IntermediateView SQL EssentialsSELF JOINSQL Essentials
Connect a table to itself
Represent a simple hierarchy with two aliases.
Level : IntermediateView SQL EssentialsJOIN · GROUP BYSQL Essentials
Calculate revenue using three tables
Follow the keys without adding a measure twice.
Level : IntermediateView SQL EssentialsCASE WHENSQL Essentials
Classify inventory risk
Transform operational thresholds into readable categories.
Level : IntermediateView SQL EssentialsNULL · COUNTSQL Essentials
Measure phone completeness
Produce a quality rate from explicit volumes.
Level : IntermediateView SQL EssentialsQuality · HAVINGSQL Essentials
Detect duplicate emails
Transform a uniqueness constraint into measurable control.
Level : IntermediateView SQL EssentialsQuality · SubqueriesSQL Essentials
Reconcile orders and payments
Compare two independent totals in a single control line.
Level : IntermediateView SQL EssentialsCTE · CalculationsSQL Essentials
Calculate the overall margin with a CTE
Separate basic measurements and derived indicators.
Level : IntermediateView SQL EssentialsCTE · TOP NSQL Essentials
Rank the top three categories
Prepare a reliable aggregate before limiting the ranking.
Level : IntermediateView SQL EssentialsCASE · AggregationsSQL Essentials
Calculate multiple statuses in one line
Build conditional indicators without multiplying queries.
Level : IntermediateView SQL EssentialsAVG · HAVINGSQL Essentials
Filter an average basket with HAVING
Apply a threshold on an aggregated indicator.
Level : IntermediateView SQL EssentialsMIN · GROUP BYSQL Essentials
Find the first order
Bring back a history to its first date per customer.
Level : IntermediateView SQL EssentialsCTE · Auto-joinSQL Essentials
Compare each month to the previous one
Align two periods to calculate an absolute evolution.
Level : IntermediateView SQL EssentialsProject · joinsSQL Essentials
Calculate margin by category
Distinguish between revenue, cost and margin on paid lines.
Level : IntermediateView SQL EssentialsProject · KPISQL Essentials
Track monthly payment rate
Combine timing and conditional aggregation into one monitorable indicator.
Level : IntermediateView SQL EssentialsWHERE · ORDER BYNo account
Filter then sort a threshold
Keep the threshold inclusive and make the outcome controllable.
Level : BeginnerOpen exerciseIN · ORDER BYDiscovery space
Select multiple brands
Express a closed list without repeating multiple OR.
Level : BeginnerCreate a free accountExpressions · AliasesDiscovery space
Calculate a unit margin
Create a simple indicator from two compatible columns.
Level : BeginnerCreate a free accountText · LENGTHDiscovery space
Control the length of names
Measure text before exporting to a limited size.
Level : BeginnerCreate a free account3 exercises are available without an account, followed by 12 more in the free Discovery space. SQL Essentials unlocks all 44 exercises. Run a first query.