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Window Functions for Analytics
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Window Functions for Analytics

EasySQL · PostgreSQL

Problem

Principal Financial Group needs a quarterly view of the strongest contributors across its retirement plans. Write a PostgreSQL query that ranks active participants by their total employee contributions during the first quarter of 2025.

Requirements

  1. Include only participants with ACTIVE status and contributions dated from January 1 through March 31, 2025.
  2. Calculate each participant's total contribution across all qualifying contribution rows.
  3. Use ROW_NUMBER() partitioned by plan_id, return the top two participants per plan, and apply deterministic tie-breaking by participant_id.
  4. Return results ordered by plan, contribution rank, and participant ID.

Schema

participants
ColumnTypeDescription
participant_idPKINTEGERUnique participant identifier
plan_idVARCHAR(30)Retirement plan identifier
participant_nameVARCHAR(100)Participant full name
statusVARCHAR(20)Participant status, such as ACTIVE or INACTIVE
contributions
ColumnTypeDescription
contribution_idPKINTEGERUnique contribution identifier
participant_idINTEGERParticipant associated with the contribution
contribution_dateDATEDate the contribution was recorded
employee_contributionNUMERIC(12,2)Employee contribution amount
Tablesparticipantscontributions
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