title: InfluxDB: INTO with multiple measurement
body: <p>I'm trying to write aggregated result from two measurements into a single measurement.</p>
  
  <p>I found on documentation that you can write multiple matching measurements with <code>:MEASUREMENT</code> keyword in <a href="https://docs.influxdata.com/influxdb/v1.7/query_language/data_exploration/#the-into-clause" rel="nofollow noreferrer">INTO query</a>. Like</p>
  
  <pre><code>SELECT * INTO "copy_NOAA_water_database"."autogen".:MEASUREMENT FROM 
  "NOAA_water_database"."autogen"./.*/
  </code></pre>
  
  <p>What I'm trying to do is aggregate from multiple measurements and write result to a single measurement.</p>
  
  <pre><code>SELECT mean("water_level") INTO 
  "copy_NOAA_water_database"."autogen"."water_agg" FROM 
  "NOAA_water_database"."autogen"./.*/ GROUP BY time(15m), *
  </code></pre>
  
  <p>The above query runs successfully, but I'm not sure whether influx has considered points from all measurement of <strong>NOAA_water_database</strong> or just last appearing measurement is considered.</p>