You can query the pg_matviews system catalog view to get ddl of a materialized view in Postgres database.
SELECT definition FROM pg_matviews WHERE schemaname='your_schema' AND matviewname='your_materialized_view';
You can query the pg_matviews system catalog view to get ddl of a materialized view in Postgres database.
SELECT definition FROM pg_matviews WHERE schemaname='your_schema' AND matviewname='your_materialized_view';