LINEST_M() returns the aggregated m value (slope) of a linear regression defined by the equation y=mx+b for a series of coordinates represented by paired numbers in x-expression and y-expression iterated over a number of records as defined by a group by clause.
Return data type: numeric
|y_value||The expression or field containing the range of y-values to be measured.|
|x_value||The expression or field containing the range of x-values to be measured.|
An optional value y0 may be stated forcing the regression line to pass through the y-axis at a given point. By stating both y0 and x0 it is possible to force the regression line to pass through a single fixed coordinate.
Unless both y0 and x0 are stated, the function requires at least two valid data-pairs to calculate. If y0 and x0 are stated, a single data pair will do.
Text values, NULL values and missing values in any or both pieces of a data-pair result in the entire data-pair being disregarded.