# google cloud platform – Computing Percentiles In BigQuery

## google cloud platform – Computing Percentiles In BigQuery

Check out APPROX_QUANTILES function in Standard SQL. If you ask for 100 quantiles – you get percentiles. So the query will look like following:

``````SELECT percentiles[offset(25)], percentiles[offset(50)], percentiles[offset(75)]
FROM (SELECT APPROX_QUANTILES(column, 100) percentiles FROM Table)
``````

In case approximate aggregation does not work for you, you might want to use the PERCENTILE_CONT function (though it will use much more memory so it might not work for huge data), e.g. the following example is from here

``````SELECT
PERCENTILE_CONT(x, 0) OVER() AS min,
PERCENTILE_CONT(x, 0.01) OVER() AS percentile1,
PERCENTILE_CONT(x, 0.5) OVER() AS median,
PERCENTILE_CONT(x, 0.9) OVER() AS percentile90,
PERCENTILE_CONT(x, 1) OVER() AS max
FROM UNNEST([0, 3, NULL, 1, 2]) AS x LIMIT 1;

+-----+-------------+--------+--------------+-----+
| min | percentile1 | median | percentile90 | max |
+-----+-------------+--------+--------------+-----+
| 0   | 0.03        | 1.5    | 2.7          | 3   |
+-----+-------------+--------+--------------+-----+
``````

#### google cloud platform – Computing Percentiles In BigQuery

You could get a fine-grain percentile profiling using the code below.

``````  SELECT
offset + 1 AS percentile,
value AS percentile_value,
FROM UNNEST((
SELECT
APPROX_QUANTILES(value, 100) as percentile_value,
FROM data_set
)) AS percentile_value  WITH OFFSET as offset
``````

Then you could get any percentile as needed.