Patterns of the Boolean expressions of simple CHECK constraints

WITH checks AS (SELECT 
o.conname AS constraint_name,
c.relname AS table_name, 
(SELECT a.attname FROM pg_attribute a WHERE a.attrelid = c.oid AND a.attnum = o.conkey[1] AND a.attisdropped = false) AS column_name,
substring(pg_get_constraintdef(o.oid),7) as consrc
FROM pg_constraint o INNER JOIN pg_class c ON c.oid = o.conrelid
WHERE o.contype = 'c' AND cardinality(o.conkey)=1
UNION ALL SELECT cc.constraint_name, cdu.table_name, cdu.column_name, regexp_replace(cc.check_clause, '^([(])(.*)([)])$','\2') AS check_clause
FROM ((INFORMATION_SCHEMA.column_domain_usage AS cdu INNER JOIN
INFORMATION_SCHEMA.tables AS t USING (table_schema, table_name)) INNER JOIN INFORMATION_SCHEMA.domain_constraints AS dc
USING (domain_schema, domain_name)) INNER JOIN INFORMATION_SCHEMA.check_constraints AS cc
USING (constraint_catalog, constraint_schema, constraint_name)
WHERE t.table_type='BASE TABLE' AND cc.check_clause NOT LIKE '%IS NOT NULL'  AND 
cdu.table_schema NOT IN (SELECT schema_name
FROM INFORMATION_SCHEMA.schemata
WHERE schema_name<>'public' AND
schema_owner='postgres' AND catalog_name IS NOT NULL AND schema_name IS NOT NULL)),
checks_pattern AS (
select replace(consrc,'('|| column_name,'(VALUE') AS pattern
FROM checks)
SELECT pattern, Count(*) AS number_of_occurrences
FROM checks_pattern
GROUP BY pattern
ORDER BY Count(*) DESC;