On Thu, Sep 28, 2017 at 3:31 PM, Seamus Abshere <sea...@abshere.net> wrote:
> > > > Does anybody have a function lying around (preferably pl/pgsql) that > > > > takes a table name and returns coverage counts? > > > > > > What is "coverage count"? > > Ah, I should have explained better. I meant how much of a column is > null. > > Basically you have to > > 0. count how many total records in a table > 1. discover the column names in a table > 2. for each column name, count how many nulls and subtract from total > count > > If nobody has one written, I'll write one and blog it. > > Thanks! > Seamus > > PS. In a similar vein, we published > http://blog.faraday.io/how-to-do-histograms-in-postgresql/ which gives > plpsql so you can do: > > SELECT * FROM histogram($table_name_or_subquery, $column_name) > > -- > Seamus Abshere, SCEA > https://www.faraday.io > https://github.com/seamusabshere > https://linkedin.com/in/seamusabshere > > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general > I can't really do the full query for you, but the following should be able to give you a head start: SELECT c.relname AS table, a.attname AS column, a.attnum AS colnum, s.stanullfrac as pct_null, s.stadistinct FROM pg_class c JOIN pg_attribute a ON a.attrelid = c.oid JOIN pg_statistic s ON (s.starelid = c.oid AND s.staattnum = a.attnum) WHERE c.relname = 'your_table_name' AND a.attnum > 0 ORDER BY 3 -- *Melvin Davidson* I reserve the right to fantasize. Whether or not you wish to share my fantasy is entirely up to you.
