Goal Find enumerated types with exactly the same values. There should not be multiple types that have the same values.
Notes The query takes into account that the sort order of values in different enumerated types could be different. For instance, the query considers types ("A", "B") and ("B", "A") as duplicates. In case of each enumerated type the query forms a list of type values that has been sorted based on the labels and uses it as the basis for grouping.
Type Problem detection (Each row in the result could represent a flaw in the design)
Reliability High (Few or no false-positive results)
License MIT License
Fixing Suggestion All but one are redundant. Drop all the types except one and use the type in case of all the columns that need the type.
Data Source INFORMATION_SCHEMA+system catalog
SQL Query
WITH enum_types AS (SELECT nspname AS type_schema, typname, array_agg(enumlabel ORDER BY enumlabel) AS values
FROM pg_catalog.pg_type t INNER JOIN pg_catalog.pg_enum e ON t.oid=e.enumtypid
INNER JOIN pg_catalog.pg_namespace n ON n.oid=t.typnamespace
WHERE 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, typname)
SELECT values, string_agg(type_schema || '.' || typname, ';
' ORDER BY type_schema, typname) AS types FROM enum_types GROUP BY values HAVING Count(*)>1 ORDER BY Count(*) DESC;

SQL statements that help generate fixes for the identified problem.

SQL Query to Generate FixDescription
WITH enum_types AS (SELECT nspname AS type_schema, typname, array_agg(enumlabel ORDER BY enumlabel) AS values
FROM pg_catalog.pg_type t INNER JOIN pg_catalog.pg_enum e ON t.oid=e.enumtypid
INNER JOIN pg_catalog.pg_namespace n ON n.oid=t.typnamespace
WHERE 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, typname),
duplicate_enum_types AS (SELECT array_agg(type_schema || '.' || typname ORDER BY type_schema, typname) AS types_array
FROM enum_types
GROUP BY values
HAVING Count(*)>1)
SELECT format('DROP TYPE %1$s;', unnest(types_array)) AS statements
FROM duplicate_enum_types
ORDER BY statements;
Drop the type. One of the types must stay in place.
Collections

This query belongs to the following collections:

NameDescription
Find problems automaticallyQueries, that results point to problems in the database. Each query in the collection produces an initial assessment. However, a human reviewer has the final say as to whether there is a problem or not .
Categories

This query is classified under the following categories:

NameDescription
Comfortability of database evolutionQueries of this category provide information about the means that influence database evolution.
Data typesQueries of this category provide information about the data types and their usage.
Duplication of implementation elementsQueries of this catergory provide information about the duplication of the database objects.
User-defined typesQueries of this category provide information about user-defined types in the database.

Further reading and related materials:

Reference
https://refactoring.guru/smells/alternative-classes-with-different-interfaces
https://refactoring.guru/smells/duplicate-code
The corresponding code smell in case of cleaning code is "G5: Duplication". (Robert C. Martin, Clean Code)