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Running Totals of Course Enrollments

MediumSQL · PostgreSQL00:00
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Your question is Running Totals of Course Enrollments. Start with the requirements and the two tables on the right.

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Problem

Cengage needs a daily enrollment trend for courses delivered through MindTap. Write a PostgreSQL query that counts confirmed enrollments by day and calculates the cumulative enrollment total from August 1 through August 5, 2025.

Requirements

  1. Join enrollments to courses and include only courses whose product_name is MindTap.
  2. Include only confirmed enrollments within the requested date range. Rows with a missing status, unmatched course, or different product must not count.
  3. Return one row per enrollment date with daily_enrollments and a chronological running_total.

Schema

courses
ColumnTypeDescription
course_idPKINTEGERUnique course identifier
course_codeVARCHAR(20)Cengage course code
course_titleVARCHAR(150)Course title
product_nameVARCHAR(50)Cengage delivery product
enrollments
ColumnTypeDescription
enrollment_idPKINTEGERUnique enrollment event identifier
course_idINTEGERReferenced course identifier
enrolled_onDATEDate of the enrollment event
enrollment_statusVARCHAR(20)Enrollment state
Tablescoursesenrollments
Your solutionPostgreSQL
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