Base table columns permitting e-mail addresses without @ sign

WITH domains AS (
SELECT cdu.table_schema, cdu.table_name, cdu.column_name, (SELECT data_type FROM INFORMATION_SCHEMA.domains AS d
WHERE d.domain_schema=dc.domain_schema AND d.domain_name=dc.domain_name) AS data_type, cc.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.column_name~*'e[_-]*(mail|meil)' 
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)),

simple_chk AS (SELECT 
(SELECT nspname FROM pg_namespace WHERE oid=c.relnamespace) AS table_schema,
c.relname as table_name, 
a.attname AS column_name,
t.typname AS type_name,
pg_get_constraintdef(o.oid) AS check_clause
FROM pg_constraint o INNER JOIN pg_class c ON c.oid = o.conrelid
INNER JOIN pg_attribute a ON a.attrelid = c.oid AND a.attnum = o.conkey[1] AND a.attisdropped = FALSE
INNER JOIN pg_type t ON a.atttypid=t.oid
WHERE cardinality(o.conkey)=1 
AND o.contype = 'c' 
AND a.attname~*'e[_-]*(mail|meil)'
UNION SELECT table_schema, table_name, column_name, data_type, check_clause
FROM domains),

suspected_columns AS (SELECT table_schema, table_name, column_name, data_type
FROM INFORMATION_SCHEMA.columns
WHERE (table_schema, table_name) IN (SELECT table_schema, table_name
FROM INFORMATION_SCHEMA.tables WHERE table_type='BASE TABLE') 
AND 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) 
AND column_name~* 'e[_-]*(mail|meil)'
AND (data_type='text' OR data_type ILIKE '%char%')),

fk_columns AS (select target_schema as table_schema, target_table as table_name, a.attname as column_name
from (select 
(select nspname from pg_namespace where oid=c.relnamespace) as target_schema,
c.relname as target_table, 
c.oid as target_table_oid,
unnest(o.conkey) AS target_col
from pg_constraint o inner join pg_class c on c.oid = o.conrelid
where o.contype = 'f') t
inner join pg_attribute a on t.target_col = a.attnum and t.target_table_oid = a.attrelid and a.attisdropped = false)

SELECT table_schema, table_name, column_name, data_type
FROM suspected_columns AS pc
WHERE NOT EXISTS (SELECT 1 FROM simple_chk AS psc WHERE pc.table_schema=psc.table_schema AND pc.table_name=psc.table_name
AND pc.column_name=psc.column_name AND check_clause LIKE '%@%') 
AND NOT EXISTS (SELECT 1 FROM fk_columns AS f WHERE pc.table_schema=f.table_schema AND pc.table_name=f.table_name
AND pc.column_name=f.column_name)
ORDER BY table_schema, table_name, column_name;