| From: | "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> |
|---|---|
| To: | Zied Kharrat <khzied(at)gmail(dot)com> |
| Cc: | pgsql-sql <pgsql-sql(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Show table and columns with null value and count |
| Date: | 2021-08-05 14:38:46 |
| Message-ID: | CAKFQuwbK=4FKvDXgrtWA3BeEpsCbzF4zQUxwFDmErpv8WsQ2gg@mail.gmail.com |
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| Thread: | |
| Lists: | pgsql-sql |
On Thu, Aug 5, 2021 at 7:09 AM Zied Kharrat <khzied(at)gmail(dot)com> wrote:
> I have a table which contains many data.
> I want to execute an sql request to show for every table, the name of the
> column, how many null value in this column, and total number of rows in
> this column.
> Could you help me?
>
If you need an exact number you will need to write some dynamic SQL using
the system catalogs to take inventory of the tables and columns in the
database.
If you can live with estimates you can simply query the statistics that are
kept by the system that it uses during query planning:
https://www.postgresql.org/docs/current/catalog-pg-statistic.html
David J.
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