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InfluxDB
Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.
I second phptherightway.com for basics. php.net is the official documentation. Do not get examples from w3schools as so much of the code there is ancient junk. The standard "first project" is to build yourself a simple database-connected api (or blog/notes web-app if you know html/js).
NOTE:
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