Well it is certainly nice to see that my choice to send my question using plain text was honored by this email service. Apologies for that mess. The output I am looking for is a series of rows with two columns, one the name of the table column, and the other the count of non-null values in a table's column of that same name, for all column names in the table.<br><br>Thanks<br><br>----------------------------------------<br>> From: dlnelson77808@xxxxxxxxxxx<br>> To: pgsql-general@xxxxxxxxxxxxxx<br>> Subject: Count of non-null values per table column<br>> Date: Fri, 14 Aug 2015 14:32:36 +0000<br>><br>> Hello list,<br><br>Apologies if this has been asked before. My search only turned up ways to list the total non-null values for all columns as a single number. I want the count for each column by column.<br><br>I have inherited a database consisting of two related huge monolithic tables that lack referential integrity between them, or even basic data constraints. One of the problems these tables have is every single non-PK column is NULLable. I am trying to understand the information that is actually stored and used so that I can implement a (hopefully) better design. Towards that end I would like to know the count of non-null values in each column per column. In other words I would like to get the following output from a table (the numbers are totally made up):<br><br>column_name | num_values<br>------------+-----------<br>col1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 5787<br>------------+-----------<br>col2&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 17<br>------------+-----------<br>col3&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 567<br>------------+-----------<br>col4&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 5787<br>------------+-----------<br>col5&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 143<br>------------+-----------<br>col6&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 1<br>------------+-----------<br>...<br><br>Is this possible through one or more of the system views, or will I need to write a function to do this? Obviously I can just issue multiple SELECT COUNT(column)... statements, but I'd rather not.<br><br>Thanks,<br>David<br>><br>> --<br>> Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx)<br>> To make changes to your subscription:<br>> http://www.postgresql.org/mailpref/pgsql-general<br> -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
