GROUP BY clause

Use the GROUP BY clause to group data by values.

GROUP BY is an optional clause used to group rows that have the same values for all columns and expressions in the list. To output an aggregation for each group, include an aggregate or selector function in the SELECT statement. When GROUP BY appears in a query, the SELECT list can only use columns that appear in the GROUP BY list or in aggregate expressions.

GROUP BY can use column aliases that are defined in the SELECT clause. GROUP BY can’t use an alias named time. In a GROUP BY list, time always refers to the measurement time column.

• Syntax
• Examples

Syntax

SELECT
  AGGREGATE_FN(field1),
  tag1
FROM measurement
GROUP BY tag1

Examples

Group data by tag values

SELECT
  AVG("water_level") AS "avg_water_level",
  "location"
FROM "h2o_feet" 
GROUP BY "location"

Group results in 15 minute time intervals by tag:

SELECT
  "location",
  DATE_BIN(INTERVAL '15 minutes', time, TIMESTAMP '2022-01-01 00:00:00Z') AS _time,
  COUNT("water_level") AS count
FROM "h2o_feet"
WHERE 
  time >= timestamp '2019-09-17T00:00:00Z'
  AND time <= timestamp '2019-09-17T01:00:00Z'
GROUP BY
  _time,
  location
ORDER BY
  location,
  _time