DO $$
DECLARE
  ALTER_QUERY text;
  CURRENT_TABLE_NAME text;
BEGIN
  FOR CURRENT_TABLE_NAME IN (
    SELECT table_name FROM INFORMATION_SCHEMA.TABLES
    WHERE table_schema = 'public'
  ) LOOP
    FOR ALTER_QUERY IN (
      select 'alter table '||table_schema||'.'||table_name||' alter column "'||column_name||'" type text;'
      from (
             select
               table_schema,
               table_name,
               column_name,
               data_type
             from INFORMATION_SCHEMA.COLUMNS
             where table_name = CURRENT_TABLE_NAME
           ) sub
      where table_schema = 'public' and (data_type = 'character varying' or data_type = 'character')
    ) LOOP
        EXECUTE ALTER_QUERY;
    END LOOP;
  END LOOP;
END;
$$;