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    Time Series Database:Merge Operations

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    Time Series Database:Merge Operations

    Last Updated:Aug 05, 2020

    In TSDB for InfluxDB®, queries automatically merge series.

    Examples

    The h2o_feet measurement in the NOAA_water_database database is included in each of the two series. The first series consists of the h2o_feet measurement and the location = coyote_creek tag. The second series consists of the h2o_feet measurement and the location = santa_monica tag.

    The following query automatically merges the two series when the query calculates the average field value of the water_level field key.

    1. > SELECT MEAN("water_level") FROM "h2o_feet"
    3. name: h2o_feet
    4. --------------
    5. time                   mean
    6. 1970-01-01T00:00:00Z   4.442107025822521

    If you want to obtain the average field value of the water_level field key for only the first series, set the value of the location tag key to coyote_creek in the WHERE clause.

    1. > SELECT MEAN("water_level") FROM "h2o_feet" WHERE "location" = 'coyote_creek'
    3. name: h2o_feet
    4. --------------
    5. time                   mean
    6. 1970-01-01T00:00:00Z   5.359342451341401

    If you want to obtain the average field value of the water_level field key for each series, include a GROUP BY clause in your query.

    1. > SELECT MEAN("water_level") FROM "h2o_feet" GROUP BY "location"
    3. name: h2o_feet
    4. tags: location=coyote_creek
    5. time                   mean
    6. ----                   ----
    7. 1970-01-01T00:00:00Z   5.359342451341401
    9. name: h2o_feet
    10. tags: location=santa_monica
    11. time                   mean
    12. ----                   ----
    13. 1970-01-01T00:00:00Z   3.530863470081006


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