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SQL Joins and Window Functions

MediumSQL · PostgreSQL00:00
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Your question is SQL Joins and Window Functions. Start with the requirements and the three tables on the right.

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Problem

Business Context

Steven Douglas Associates wants a recruiter-facing view of candidate applications and interview performance. Applications without scored feedback must remain visible so recruiters can identify records needing review.

Task

Write a PostgreSQL query that joins candidates, applications, and interview feedback to rank each candidate's qualifying applications.

Requirements

  1. Include applications submitted during the first quarter of 2025, excluding withdrawn applications.
  2. Calculate each application's average interview score and feedback count.
  3. Rank applications per candidate by average score descending, then submission date descending, using ROW_NUMBER().
  4. Label applications as Recommended, Review, or Needs review with CASE.

Schema

candidates
ColumnTypeDescription
candidate_idPKINTUnique candidate identifier
candidate_nameVARCHAR(100)Candidate's full name
emailVARCHAR(150)Candidate email address
applications
ColumnTypeDescription
application_idPKINTUnique application identifier
candidate_idINTReferences candidates.candidate_id
position_titleVARCHAR(150)Position associated with the application
submitted_atDATEDate the application was submitted
statusVARCHAR(30)Application workflow status
interview_feedback
ColumnTypeDescription
feedback_idPKINTUnique feedback identifier
application_idINTReferences applications.application_id
interviewer_nameVARCHAR(100)Interviewer providing feedback
scoreNUMERIC(5,2)Interview score from 0 to 100
recommendationVARCHAR(30)Interviewer's recommendation
Tablescandidatesapplicationsinterview_feedback
Your solutionPostgreSQL
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