Statistics metadata in TAP

[Mark Taylor]

On Thu, 20 Oct 2016, Walter Landry wrote:

> As a side point, I am a little worried about what it means to take the
> mean of a table with NULL's.  I can define it, but I do not know if I
> like it.

Seems pretty straightforward and unobjectionable to me: sum the
non-null values and divide by the number of non-null values.
I presume that's what ADQL/SQL AVG does.

--
Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
m.b.taylor at bris.ac.uk +44-117-9288776  http://www.star.bris.ac.uk/~mbt/