forecasting with linear regression

Advanced SQL for Data Science - Time Series/03.Time Series Analysis/06.Forecasting with Linear Regression.sql

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+/************ Forecasting with Linear Regression **************/
+
+/* 
+
+so far, we have been working with past data.
+Now we want to make future predictions based on those past data using Linear Regression.
+
+y=mx + b
+m: slope
+b: y intercept
+y: predicted value
+x: input value
+
+Let's try and predict the amount of free memory will be available given a particular CPU utilization.
+*/
+
+-- first we will find m and b values : m = -0.46684018640161745, b = 0.6664934543856621 
+SELECT
+	REGR_SLOPE(free_memory, cpu_utilization) AS m,
+	REGR_INTERCEPT(free_memory, cpu_utilization) AS b
+FROM time_series.utilization
+WHERE event_time BETWEEN '2019-03-05' AND '2019-03-06';
+
+
+-- let's say we want to predict free memory based on 65% CPU utilization
+-- we predicted 0.36304733322461075 (about 36% of free memory)
+SELECT
+	REGR_SLOPE(free_memory, cpu_utilization) * 0.65 + 
+	REGR_INTERCEPT(free_memory, cpu_utilization) AS b
+FROM time_series.utilization
+WHERE event_time BETWEEN '2019-03-05' AND '2019-03-06';
+
+
+
+
+