Optional base table columns

SELECT A.table_schema, A.table_name , A.column_name, CASE WHEN data_type ILIKE 'character%' AND character_maximum_length IS NOT NULL THEN data_type || '(' || character_maximum_length::text || ')'
WHEN data_type ILIKE 'timestamp%' AND datetime_precision IS NOT NULL THEN data_type || '(' || datetime_precision || ')'
WHEN data_type ILIKE 'numeric%' AND numeric_precision IS NOT NULL THEN data_type || '(' || numeric_precision::text || ',' ||coalesce(numeric_scale,0)::text || ')'
WHEN data_type ILIKE 'interval%' AND interval_type IS NOT NULL THEN data_type || '(' || interval_type::text || ')'
WHEN data_type='USER-DEFINED' THEN udt_schema || '.' || udt_name 
ELSE data_type END AS data_type
FROM information_schema.columns A INNER JOIN information_schema.tables T USING (table_schema, table_name)
INNER JOIN information_schema.schemata S ON A.table_schema=S.schema_name
WHERE is_nullable='YES' AND T.table_type='BASE TABLE'
AND (A.table_schema = 'public'
OR S.schema_owner<>'postgres')
ORDER BY A.table_schema, A.table_name, A.ordinal_position;