September 2018
Intermediate to advanced
412 pages
11h 12m
English
book
Industrial Internet Application Development
by Alena Traukina, Jayant Thomas, Prashant Tyagi, Veera Kishore Reddipalli
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Example – count the field values associated with a field key
The COUNT(*) function returns the number of non-null field values:
> SELECT COUNT("water_level") FROM "h2o_feet" name: h2o_feet time count ---- ----- 1970-01-01T00:00:00Z 15258
The output is the number of non-null field values for the water_level field key in the h2o_feet measurement.