select
 col.table_name as 表名,
 col.column_name as 字段名,
 col.data_type as 字段类型,
 des.description as 字段描述
 from
 information_schema.columns col left join pg_description des on
 col.table_name::regclass = des.objoid
 and col.ordinal_position = des.objsubid
 where
 table_schema = 'public'
 --and table_name = 'xxx'
 order by
 col.table_name;