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MoM Retention for Student Profiles

MediumSQL · PostgreSQL00:00
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Your question is MoM Retention for Student Profiles. Start with the requirements and the two tables on the right.

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Problem

Write a SQL query to calculate the month-over-month retention rate of active student profiles on Handshake - stryder.

Use student_profiles and profile_activity. Treat a profile as active in a month when it has at least one activity record during that month and its profile status is active. Retention for a month is the share of profiles active in the previous month that are also active in the current month.

Output

  1. One row per month with a prior-month active population.
  2. Columns: month_start, prior_month_active_profiles, retained_profiles, and retention_rate.
  3. Sort by month_start ascending, with the rate rounded to four decimal places.

Schema

student_profiles
ColumnTypeDescription
profile_idPKINTUnique student profile identifier
profile_statusVARCHAR(20)Current profile status
school_nameVARCHAR(120)Student's school
profile_activity
ColumnTypeDescription
activity_idPKINTUnique activity record identifier
profile_idINTStudent profile associated with the activity
activity_dateDATEDate on which the activity occurred
activity_typeVARCHAR(30)Type of profile activity
Tablesstudent_profilesprofile_activity
Your solutionPostgreSQL
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