It still came through as junk. But I reconstructed it below
=== original message ===
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.
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):
column_name | num_values
------------+-----------
col1 | 5787
------------+-----------
col2 | 17
------------+-----------
col3 | 567
------------+-----------
col4 | 5787
------------+-----------
col5 | 143
------------+-----------
col6 | 1
------------+-----------
====
I assume what "num_values" contains is the _distinctly different_ number of values in "column_name" for each and every column name in a table. E.g. if "col1" contains value 'x' twice and 'y' ten times,then "num_values" would be 2, not 12. Or do you really want the 12? I'm unsure.
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