Goal The value that is returned by a function should depend on something. If you do not have anything meaningful to return (for instance, the function always returns true, false, NULL, or the same number), then write VOID instead of the return type.
Notes Refers to the column pg_proc.prokind and thus works starting from PostgreSQL 11. In the returned body of routine the query replaces each newline character with the line break (br) tag for the better readability in case the query result is displayed in a web browser. There could be multiple routines with the same name but with different parameters in the same schema (overloading). Thus, for the unique identification of the routine it is necessary to present also its parameters in addition to the schema name and routine name.
Type Problem detection Each row in the result could represent a flaw in the design
Reliability Medium Medium number of false-positive results
License MIT (opens in new tab)
Fixing Suggestion Change the function so that it returns a different value depending on the circumstances or does not return a value at all.
Data Source INFORMATION_SCHEMA+system catalog
SQL Query 
SELECT 
  n.nspname AS func_schema, 
  pr.proname AS func_name, 
   pg_get_function_identity_arguments(pr.oid) AS parameters,
  regexp_replace(pg_get_functiondef(pr.oid),'[\r\n]','<br>','g')  AS func_src
FROM 
  pg_catalog.pg_proc pr, 
  pg_catalog.pg_namespace n,
  pg_catalog.pg_language l,
  pg_catalog.pg_type t
WHERE 
  pr.pronamespace = n.oid 
  AND pr.prolang=l.oid 
  AND pr.prorettype=t.oid 
  AND pr.prokind='f' 
  AND l.lanname='plpgsql' 
  AND t.typname<>'void' 
  AND t.typname<>'trigger' 
  AND pg_get_functiondef(pr.oid)!~*'RETURN[[:space:]].+RETURN[[:space:]]' 
  AND pg_get_functiondef(pr.oid)~*'RETURN[[:space:]]+(NULL|TRUE|FALSE|[[:digit:]])' 
AND n.nspname NOT IN (SELECT schema_name
FROM INFORMATION_SCHEMA.schemata
WHERE schema_name<>'public' AND
schema_owner='postgres' AND schema_name IS NOT NULL)
ORDER BY func_schema, func_name, parameters;

Collections

This query belongs to the following collections:

Find problems automatically

Queries, 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 .

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:

User-defined routines

Queries of this category provide information about the user-defined routines

NameDescription
User-defined routinesQueries of this category provide information about the user-defined routines