代码

select
	c.relname as 表名,
	a.attname as 列名,
	(case
		when a.attnotnull = true then true
		else false end) as 非空,
	(case
		when (
		select
			count(pg_constraint.*)
		from
			pg_constraint
		inner join pg_class on
			pg_constraint.conrelid = pg_class.oid
		inner join pg_attribute on
			pg_attribute.attrelid = pg_class.oid
			and pg_attribute.attnum = any(pg_constraint.conkey)
		inner join pg_type on
			pg_type.oid = pg_attribute.atttypid
		where
			pg_class.relname = c.relname
			and pg_constraint.contype = 'p'
			and pg_attribute.attname = a.attname) > 0 then true
		else false end) as 主键,
	concat_ws('', t.typname) as 字段类型,
	(case
		when a.attlen > 0 then a.attlen
		when t.typname='bit' then a.atttypmod
		else a.atttypmod - 4 end) as 长度,
	 col.is_identity	as 自增,
	 col.column_default	as 默认值,
	(select description from pg_description where objoid = a.attrelid
	and objsubid = a.attnum) as 备注
from
	pg_class c,
	pg_attribute a ,
	pg_type t,
	information_schema.columns as col
where
	c.relname = 'live_camerainfo'
	and a.attnum>0
	and a.attrelid = c.oid
	and a.atttypid = t.oid
	and col.table_name=c.relname and col.column_name=a.attname
order by
	c.relname desc,
	a.attnum asc

效果

*注释为空的字段也能正常显示，能正确显示bit类别长度