Groepen vergelijken

Rapporteren in SQL

Tyler Pernes

Learning & Development Consultant

Soorten metrics

Volume-metrics
Efficiëntie-metrics

Volume-metrics

Schalen met de omvang

Volume-metrics

Schalen met de omvang

Volume-metrics

Schalen met de omvang

Percentage van totaal berekenen

basketball_points table
+----------+------------+---------+
| team_id  | player_id  | points  |
|----------|------------|---------|
| 1        | 482        | 92      |
| 1        | 165        | 47      |
| 2        | 222        | 64      |
+----------+------------+---------+

SELECT team_id, SUM(points) AS points
FROM basketball_points
GROUP BY team_id;

Percentage van totaal berekenen

basketball_points-tabel
+----------+------------+---------+
| team_id  | player_id  | points  |
|----------|------------|---------|
| 1        | 482        | 92      |
| 1        | 165        | 47      |
| 2        | 222        | 64      |
+----------+------------+---------+

+----------+---------+
| team_id  | points  |
|----------|---------|
| 1        | 782     |
| 2        | 625     |
| 3        | 487     |
| 4        | 398     |
+----------+---------+

Percentage van totaal berekenen

Stap 1: totaal berekenen

SELECT 
    team_id, 
    SUM(points) AS points
    SUM(points) OVER () AS total_points
FROM basketball_points
GROUP BY team_id;

Stap 2: percentage van totaal berekenen

SELECT 
    team_id, 
    SUM(points) AS points
    SUM(points) / SUM(points) OVER () AS perc_of_total
FROM basketball_points
GROUP BY team_id;

Percentage van totaal berekenen

Resultaten:

+----------+---------+---------------+
| team_id  | points  | perc_of_total |
|----------|---------|---------------|
| 1        | 782     | .34           |
| 2        | 625     | .27           |
| 3        | 487     | .21           |
| 4        | 398     | .17           |
+----------+---------+---------------+

Percentage van totaal berekenen

Percentage punten gescoord per speler voor elk team:

SELECT 
    player_id,
    team_id,
    SUM(points) AS points
    SUM(points) / (SUM(points) OVER (PARTITION BY team_id)) AS perc_of_team
FROM basketball_points
GROUP BY player_id, team_id;

Percentage van totaal berekenen

Resultaten:

+-----------+---------+---------+--------------+
| player_id | team_id | points  | perc_of_team |
|-----------|---------|---------|--------------|
| 482       | 1       | 92      | .12          |
| 165       | 1       | 47      | .06          |
| 222       | 2       | 64      | .10          |
+-----------+---------+---------+--------------+

Efficiëntie-metrics

Schalen niet met de omvang
Meestal een ratio

Efficiëntie-metrics

Schalen niet met de omvang
Meestal een ratio

Efficiëntie-metrics

Schalen niet met de omvang
Meestal een ratio

Prestatie-index

Vergelijkt performance met een benchmark
Benchmark is vaak gemiddelde of mediaan

Prestatie-index

basketball_summary-tabel
+----------+--------+---------+
| team_id  | games  | points  |
|----------|--------|---------|
| 1        | 24     | 782     |
| 2        | 20     | 625     |
| 3        | 12     | 487     |
+----------+--------+---------+

Punten per wedstrijd-prestatie?

Prestatie-index

Stap 1: punten per wedstrijd per team

SELECT 
    team_id, 
    points/games AS team_ppg
FROM basketball_summary;

Stap 2: punten per wedstrijd voor de hele league

SELECT 
    team_id, 
    points/games AS team_ppg,
    SUM(points) OVER () / SUM(games) OVER () AS league_ppg
FROM basketball_summary;

Prestatie-index

Stap 3: prestatie-index

SELECT 
    team_id, 
    points/games AS team_ppg,
    SUM(points) OVER () / SUM(games) OVER () AS league_ppg,
    (points/games) 
    / 
    (SUM(points) OVER () / SUM(games) OVER ()) AS perf_index
FROM basketball_summary;

Prestatie-index

Stap 3: prestatie-index

+----------+----------+------------+-------------+
| team_id  | team_ppg | league_ppg | perf_index  |    
|----------|----------|------------|-------------|
| 1        | 32.6     | 33.8       | 0.96        |
| 2        | 31.3     | 33.8       | 0.92        |
| 3        | 40.6     | 33.8       | 1.20        |
+----------+----------+------------+-------------+

¹ De resultaten laten duidelijk zien dat team drie 20% meer punten scoort dan het leaguegemiddelde.

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Rapporteren in SQL