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WITH number_of_cols AS (SELECT table_schema, table_name, table_type, Count(c.table_schema) AS number_of_columns
FROM INFORMATION_SCHEMA.tables AS t LEFT JOIN information_schema.columns AS c USING  (table_schema, table_name) 
WHERE t.table_schema NOT IN (SELECT schema_name
FROM INFORMATION_SCHEMA.schemata
WHERE schema_name<>'public' AND
schema_owner='postgres' AND schema_name IS NOT NULL) 
GROUP BY table_schema, table_name, table_type
UNION SELECT nspname, relname, 'MATERIALIZED VIEW' AS table_type, Count(*) AS number_of_columns
FROM pg_class INNER JOIN pg_namespace ON pg_class.relnamespace=pg_namespace.oid
LEFT JOIN pg_attribute ON pg_class.oid=pg_attribute.attrelid
WHERE relkind = 'm' AND attnum>=1 AND 
nspname NOT IN (SELECT schema_name
FROM INFORMATION_SCHEMA.schemata
WHERE schema_name<>'public' AND
schema_owner='postgres' AND schema_name IS NOT NULL)
GROUP BY nspname, relname)
SELECT table_type, table_schema, table_name, number_of_columns
FROM number_of_cols
WHERE number_of_columns<=1
ORDER BY table_schema, table_type, table_name, number_of_columns DESC;