postgresql 查询指定模式下表字段信息SQL语句

# 方式1：（支持查询指定模式schema下某张表的字段信息）
  SELECT  a.attname AS field, t.typname AS type
  FROM 
    (select c.relname,c.oid,n.nspname from pg_class c left join pg_catalog.pg_namespace n on c.relnamespace = n.oid) u,
    pg_attribute a,
      pg_type t
  WHERE 
    u.relname = '实际的表名'
    AND u.nspname = '实际的schema名称'
      AND a.attnum > 0
      AND a.attrelid = u.oid
      AND a.atttypid = t.oid
  ORDER BY 
    a.attnum;



# 方式:2：
  SELECT a.attnum, a.attname AS field, t.typname AS type, a.attlen AS length, a.atttypmod AS lengthvar
      , a.attnotnull AS notnull, b.description AS comment
  FROM pg_class c, pg_attribute a
      LEFT JOIN pg_description b
      ON a.attrelid = b.objoid
          AND a.attnum = b.objsubid, pg_type t
  WHERE c.relname = '实际的表名'
      AND a.attnum > 0
      AND a.attrelid = c.oid
      AND a.atttypid = t.oid
  ORDER BY a.attnum;