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Segment Customers into Quartiles

intermediate~10 min25 pts
📊 View Insights

Problem

The marketing team wants to segment customers into 4 groups (quartiles) based on their total spending. This will help target high-value customers differently.

Write a SQL query that first calculates total spending per customer, then uses NTILE(4) to divide them into quartiles.

Schema: Customer

ColumnType
CustomerIdINTEGER (Primary Key)
FirstNameTEXT
LastNameTEXT
CompanyTEXT
AddressTEXT
CityTEXT
StateTEXT
CountryTEXT
PostalCodeTEXT
PhoneTEXT
FaxTEXT
EmailTEXT
SupportRepIdINTEGER (Foreign Key → Employee.EmployeeId)

Schema: Invoice

ColumnType
InvoiceIdINTEGER (Primary Key)
CustomerIdINTEGER (Foreign Key → Customer.CustomerId)
InvoiceDateTIMESTAMP
BillingAddressTEXT
BillingCityTEXT
BillingStateTEXT
BillingCountryTEXT
BillingPostalCodeTEXT
TotalNUMERIC(10,2)

Requirements:

  • Calculate total spending per customer
  • Use NTILE(4) to divide into 4 equal groups
  • Return FirstName, LastName, TotalSpent, and Quartile
  • Order by TotalSpent descending, then CustomerId ascending to break ties

About NTILE:

NTILE(n) divides rows into n roughly equal buckets and assigns a bucket number (1 to n) to each row.

Window FunctionsNTILEGROUP BYJOINAggregation
📊
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SQL Editor

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