GaussDB(DWS) 快速查到一张表的列信息

information_schema下的视图在数据库中对象较多时返回结果很慢，可以通过以下sql快速查询到一张或几张表的列信息：

select /*+ nestloop(a c)*/ c.column_name, c.data_type, c.ordinal_position, pgd.description, pp.partkey, c.is_nullable, c.column_default, c.character_maximum_length, c.numeric_precision, 
c.numeric_scale, c.datetime_precision, c.interval_type, c.udt_name
from information_schema.columns as c left join pg_namespace sp on sp.nspname = c.table_schema left join pg_class cla on cla.relname = c.table_name and cla.relnamespace = sp.oid
left join pg_catalog.pg_partition pp on (pp.parentid = cla.oid and pp.parttype = 'r') left join pg_catalog.pg_description pgd on (pgd.objoid=cla.oid and pgd.objsubid = c.ordinal_position)
where c.table_name in ('t1') and c.table_schema = 'public';

使用时可以将table_name和table_schema替换成需要查询的模式名和表名。

查询结果如下：

 column_name | data_type | ordinal_position |  description  | partkey | is_nullable | column_default | character_maximum_length | numeric_precision | numeric_scale | datetime_precision | interval_type | udt_name 
-------------+-----------+------------------+---------------+---------+-------------+----------------+--------------------------+-------------------+---------------+--------------------+---------------+----------
 b           | integer   |                2 | second column |         | YES         |                |                          |                32 |             0 |                    |               | int4
 a           | integer   |                1 | first column  |         | YES         |                |                          |                32 |             0 |                    |               | int4
(2 rows)