# See a column's distribution Shape / inspect histogram, quantiles of one column Page: ## Status Runs as a SQL step. arcform carries it as a `sql:` step today. ## The DuckDB step quantiles and a histogram It reads the `orders` table the proofs share. Create it first: ```sql CREATE TABLE orders AS SELECT * FROM (VALUES (1, 'Alice Ng', 'north', DATE '2026-01-03', 120.00, 'widget', 'a|b', '{"channel":"web","items":[1,2]}'), (2, 'alice ng', 'north', DATE '2026-01-05', 80.50, 'gadget', 'b', '{"channel":"shop","items":[3]}'), (3, 'Bob Okafor', 'south', DATE '2026-01-05', 300.00, 'widget', 'a|c', '{"channel":"web","items":[4,5,6]}'), (4, 'Carla Díaz', 'east', DATE '2026-01-09', NULL, 'gizmo', NULL, '{"channel":"web","items":[]}'), (5, 'Bob Okafor', 'south', DATE '2026-01-12', 45.25, 'gadget', 'c', '{"channel":"phone","items":[7]}'), (6, 'Dev Patel', 'west', DATE '2026-01-12', 510.00, 'widget', 'a', '{"channel":"web","items":[8,9]}'), (7, 'Carla Diaz', 'east', DATE '2026-01-20', 99.99, 'gizmo', 'b|c', '{"channel":"shop","items":[10]}'), (8, 'Dev Patel', 'west', DATE '2026-02-02', 510.00, 'widget', 'a', '{"channel":"web","items":[8,9]}'), (9, 'Eve Larsen', NULL, DATE '2026-02-03', 15.00, 'gadget', NULL, '{"channel":"web","items":[11]}'), (10, 'Alice Ng', 'north', DATE '2026-02-10', 220.00, 'gizmo', 'a|b|c', '{"channel":"phone","items":[12,13]}') ) t(order_id, customer, region, order_date, amount, product, tags, meta); ``` Then run the statement: ```sql CREATE TEMP TABLE result AS SELECT quantile_cont(amount, [0.25, 0.5, 0.75]) AS quartiles, histogram(amount) AS hist FROM orders; SELECT * FROM result; SELECT CASE WHEN ((SELECT quartiles = [80.5, 120.0, 300.0] AND hist[510.00] = 2 FROM result)) THEN 'as expected' ELSE error('the quartiles or the count of the repeated amount is wrong') END AS verdict; ``` It needs nothing installed beyond DuckDB itself. ## Variants - Count values in bins: Show how often a column's values fall in each range or category, as a histogram, density or facet. - Summarise with quantiles and moments: Reduce a column to statistics of its distribution, such as quantiles, median, mode, skewness, kurtosis or entropy. ## What other tools call it Meridian's classification; an independent blind rating agreed on 86.2% of 312 rows (exact class, version 2). - Alteryx Designer: [`Histogram`](https://help.alteryx.com/current/en/designer/tools/data-investigation/histogram-tool.html) (read 2026-09-27) - Alteryx Designer: [`Violin Plot`](https://help.alteryx.com/current/en/designer/tools/data-investigation/violin-plot-tool.html) (read 2026-09-27) - DuckDB: [`approx_quantile`](https://duckdb.org/docs/current/sql/functions/aggregates) (read 2026-09-27) - DuckDB: [`approx_top_k`](https://duckdb.org/docs/current/sql/functions/aggregates) (read 2026-09-27) - DuckDB: [`entropy`](https://duckdb.org/docs/current/sql/functions/aggregates) (read 2026-09-27) - DuckDB: [`histogram`](https://duckdb.org/docs/current/sql/functions/aggregates) (read 2026-09-27) - DuckDB: `histogram` (read 2026-09-27) - DuckDB: [`histogram_exact`](https://duckdb.org/docs/current/sql/functions/aggregates) (read 2026-09-27) - DuckDB: `histogram_values` (read 2026-09-27) - DuckDB: [`kurtosis`](https://duckdb.org/docs/current/sql/functions/aggregates) (read 2026-09-27) - DuckDB: [`kurtosis_pop`](https://duckdb.org/docs/current/sql/functions/aggregates) (read 2026-09-27) - DuckDB: [`mad`](https://duckdb.org/docs/current/sql/functions/aggregates) (read 2026-09-27) - DuckDB: [`median`](https://duckdb.org/docs/current/sql/functions/aggregates) (read 2026-09-27) - DuckDB: [`mode`](https://duckdb.org/docs/current/sql/functions/aggregates) (read 2026-09-27) - DuckDB: [`quantile`](https://duckdb.org/docs/current/sql/functions/aggregates) (read 2026-09-27) - DuckDB: [`quantile_cont`](https://duckdb.org/docs/current/sql/functions/aggregates) (read 2026-09-27) - DuckDB: [`quantile_disc`](https://duckdb.org/docs/current/sql/functions/aggregates) (read 2026-09-27) - DuckDB: [`reservoir_quantile`](https://duckdb.org/docs/current/sql/functions/aggregates) (read 2026-09-27) - DuckDB: [`skewness`](https://duckdb.org/docs/current/sql/functions/aggregates) (read 2026-09-27) - AWS Glue: [`Distribution`](https://docs.aws.amazon.com/glue/latest/dg/dqdl-rule-types.html) (read 2026-09-27) - OpenRefine: [`1-bounded numeric log facet`](https://openrefine.org/docs/manual/facets#numeric-log-facet) (read 2026-09-27) - OpenRefine: [`Best candidate's name edit distance`](https://openrefine.org/docs/manual/reconciling#reconciliation-facets) (read 2026-09-27) - OpenRefine: [`Best candidate's name word similarity`](https://openrefine.org/docs/manual/reconciling#reconciliation-facets) (read 2026-09-27) - OpenRefine: [`Best candidate's score`](https://openrefine.org/docs/manual/reconciling#reconciliation-facets) (read 2026-09-27) - OpenRefine: [`Custom numeric facet`](https://openrefine.org/docs/manual/facets#custom-numeric-facet) (read 2026-09-27) - OpenRefine: [`Log of text-length facet`](https://openrefine.org/docs/manual/facets#text-length-facet) (read 2026-09-27) - OpenRefine: [`Numeric facet`](https://openrefine.org/docs/manual/facets#numeric-facet) (read 2026-09-27) - OpenRefine: [`Numeric log facet`](https://openrefine.org/docs/manual/facets#numeric-log-facet) (read 2026-09-27) - OpenRefine: [`Text-length facet`](https://openrefine.org/docs/manual/facets#text-length-facet) (read 2026-09-27) - OpenRefine: [`Timeline facet`](https://openrefine.org/docs/manual/facets#timeline-facet) (read 2026-09-27) - OpenRefine: [`Unicode character-code facet`](https://openrefine.org/docs/manual/facets#unicode-character-code-facet) (read 2026-09-27) - Polars: [`Expr.hist`](https://docs.pola.rs/api/python/stable/reference/expressions/computation.html) (read 2026-09-27) - Tableau Prep: [`Profile pane`](https://help.tableau.com/current/prep/en-us/prep_about.htm) (read 2026-09-27)