Goal Find subqueries of derived tables (views, materialized views) with the LIMIT/FETCH clause or with DISTINCT ON construct but without the ORDER BY clause. These constructs require sorting to produce a meaningful result.
Notes In the returned subquery of view/materialized view 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.
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
Data Source INFORMATION_SCHEMA+system catalog
SQL Query
SELECT
table_schema,
table_name,
type,
regexp_replace(view_definition,'[\r\n]','
','g') AS view_definition FROM (SELECT views.table_schema, views.table_name, 'VIEW' AS type, views.view_definition FROM information_schema.views WHERE 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) UNION SELECT schemaname, matviewname, 'MATERIALIZED VIEW' AS type, definition FROM pg_catalog.pg_matviews) AS foo WHERE view_definition !~*'[[:space:]]+order[[:space:]]+by[[:space:]]+' AND view_definition ~*'([[:space:]]+limit[[:space:]]+|[[:space:]]+fetch[[:space:]]+first[[:space:]]+|[[:space:]]+distinct[[:space:]]+on[[:space:]]+)' ORDER BY table_schema, table_name;
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
Derived tablesQueries of this category provide information about the derived tables (views, materialized views), which are used to implement virtual data layer.
Validity and completenessQueries of this category provide information about whether database design represents the world (domain) correctly (validity) and whether database design captures all the information about the world (domain) that is correct and relevant (completeness).

Further reading and related materials:

Reference
https://www.geekytidbits.com/postgres-distinct-on/