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Pie & Doughnut Charts

Pie and doughnut charts show how individual slices make up a whole. They are ideal for proportions — the share of customers per plan, sales per region, or tickets per status. A doughnut is the same chart with a hollow centre.

Building one​

Provide a category column and a single numeric column:

SELECT
  status        AS "Status",
  COUNT(*)      AS "Tickets"
FROM tickets
GROUP BY status
ORDER BY COUNT(*) DESC;

Status supplies the slice labels and Tickets supplies the slice sizes. Choose Pie or Doughnut as the chart type.

Keep the slices few​

Pie and doughnut charts are only readable with a handful of slices. If your query returns many categories, group the small ones together in SQL:

SELECT
  CASE WHEN rn <= 5 THEN status ELSE 'Other' END AS "Status",
  SUM(cnt) AS "Tickets"
FROM (
  SELECT status, COUNT(*) AS cnt,
         ROW_NUMBER() OVER (ORDER BY COUNT(*) DESC) AS rn
  FROM tickets
  GROUP BY status
) t
GROUP BY CASE WHEN rn <= 5 THEN status ELSE 'Other' END;

Pie vs. doughnut​

The two are interchangeable — pick whichever reads better in your layout. The doughnut's empty centre works nicely on a compact dashboard tile.

Tips​

  • Use a single numeric series — pie/doughnut charts plot one value per slice.
  • Sort by size with ORDER BY so the largest slice leads.
  • For comparing many categories, prefer a bar chart instead.