通过表名获取表的字段参数

【Oracle】

select tc.COLUMN_NAME as fieldCode,
       tc.DATA_TYPE   as dataType,
       cc.comments    as fieldName
  from user_tab_columns tc, user_col_comments cc
 where tc.TABLE_NAME = cc.table_name
   and tc.COLUMN_NAME = cc.column_name
   and tc.Table_Name = '表名'
 order by tc.COLUMN_ID

【SQL Server】

SELECT a.name as fieldCode,b.name as dataType,isnull(g.[value],'') as fieldName 
					 FROM  
					 syscolumns a left join systypes b 
					 on a.xusertype=b.xusertype  
					 inner join sysobjects d 
					 on a.id=d.id  and d.xtype='U' and  d.name<>'dtproperties' 
					 left join syscomments e 
					 on a.cdefault=e.id 
					 left join sys.extended_properties   g 
					 on a.id=G.major_id and a.colid=g.minor_id   
					 left join sys.extended_properties f 
					 on d.id=f.major_id and f.minor_id=0 
					 where d.name='表名';

【PostgreSQL】

SELECT a.attname AS fieldcode,t.typname AS datatype,b.description AS fieldname 
FROM pg_class c,pg_attribute a 
LEFT OUTER JOIN pg_description b 
ON a.attrelid=b.objoid AND a.attnum = b.objsubid,pg_type t 
WHERE c.relname = 'trwrq'and a.attnum > 0 and a.attrelid = c.oid and a.atttypid = t.oid ORDER BY a.attnum;