Exclude constraint to prevent overlapping time periods

Copy SQL

with excl as (select 
o.conname, 
(select nspname from pg_namespace where oid=c.relnamespace) as excl_schema,
c.relname as excl_table, 
c.oid as excl_table_oid,
o.conkey AS excl_col,
o.conexclop AS excl_op,
pg_get_constraintdef(o.oid) as const_def
from pg_constraint o inner join pg_class c on c.oid = o.conrelid
where o.contype in ('x') ),
excl_unnest as (select conname, excl_schema, excl_table, excl_table_oid, excl_col, excl_col_num, ordin_col, const_def, excl_op
from excl, unnest(excl.excl_col) with ordinality as k(excl_col_num, ordin_col)),
excl_with_names as (select conname, excl_schema, excl_table,  array_agg(a_key.attname order by ordin_col) as excl_col, const_def, excl_op 
from excl_unnest k left join pg_attribute a_key on k.excl_col_num = a_key.attnum and k.excl_table_oid = a_key.attrelid and a_key.attisdropped = false
group by conname, excl_schema, excl_table, const_def, excl_op),
excl_unnest_op as (select conname, excl_schema, excl_table, excl_col, const_def, excl_op, excl_op_num, ordin_op
from excl_with_names, unnest(excl_with_names.excl_op) with ordinality as k(excl_op_num, ordin_op)),
excl_with_names_op as (select conname, excl_schema, excl_table, excl_col, const_def, array_agg(op.oprname order by ordin_op) as excl_op
from excl_unnest_op k inner join pg_operator op on k.excl_op_num=op.oid
group by conname, excl_schema, excl_table, excl_col, const_def),
multiple_temp AS (SELECT table_schema, table_name
FROM INFORMATION_SCHEMA.columns
WHERE data_type~*'(date|timestamp)'
AND (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)
GROUP BY table_schema, table_name
HAVING Count(*)>1)
SELECT conname, excl_schema, excl_table, excl_col, excl_op, const_def
FROM excl_with_names_op
WHERE (excl_schema, excl_table) IN (SELECT table_schema, table_name
FROM multiple_temp)
AND excl_op::text~'&&'
ORDER BY excl_schema, excl_table, excl_col;