SELECT Count(*) FILTER (WHERE C.is_nullable='YES') AS number_of_optional_columns,
Count(*) AS number_of_columns,
Round(Count(*) FILTER (WHERE C.is_nullable='YES')::decimal*100/Count(*)::decimal,1) AS percentage_of_optional_columns
FROM information_schema.columns C INNER JOIN information_schema.tables T USING (table_schema, table_name)
INNER JOIN information_schema.schemata S ON T.table_schema = S.schema_name
WHERE T.table_type = 'BASE TABLE'
AND (T.table_schema = 'public' OR S.schema_owner<>'postgres');
Collections
This query belongs to the following collections:
Name
Description
Find problems about integrity constraints
A selection of queries that return information about the state of integrity constraints in the datadabase. Contains all the types of queries - problem detection, software measure, and general overview
Find problems by overview
Queries that results point to different aspects of database that might have problems. A human reviewer has to decide based on the results as to whether there are problems or not .
Find quick numeric overview of the database
Queries that return numeric values showing mostly the number of different types of database objects in the database
Categories
This query is classified under the following categories:
Name
Description
Missing data
Queries of this category provide information about missing data (NULLs) in a database.