SQL SERVER
查看所有表名：
select name from sysobjects where type=\'U\'
查询表的所有字段名：
Select name from syscolumns Where ID=OBJECT_ID(\'表名\')
select * from information_schema.tables
select * from information_schema.views
select * from information_schema.columns
查询某个表的列名称、说明、备注、类型等
------sqlserver 查询某个表的列名称、说明、备注、类型等
SELECT
表名 = case when a.colorder=1 then d.name else \'\' end,
表说明 = case when a.colorder=1 then isnull(f.value,\'\') else \'\' end,
字段序号 = a.colorder,
字段名 = a.name,
标识 = case when COLUMNPROPERTY( a.id,a.name,\'IsIdentity\')=1 then \'√\'else \'\' end,
主键 = case when exists(SELECT 1 FROM sysobjects where xtype=\'PK\' and parent_obj=a.id and name in (
SELECT name FROM sysindexes WHERE indid in( SELECT indid FROM sysindexkeys WHERE id = a.id AND colid=a.colid))) then \'√\' else \'\' end,
类型 = b.name,
占用字节数 = a.length,
长度 = COLUMNPROPERTY(a.id,a.name,\'PRECISION\'),
小数位数 = isnull(COLUMNPROPERTY(a.id,a.name,\'Scale\'),0),
允许空 = case when a.isnullable=1 then \'√\'else \'\' end,
默认值 = isnull(e.text,\'\'),
字段说明 = isnull(g.[value],\'\')
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=\'Sys_User\' --如果只查询指定表,加上此where条件，tablename是要查询的表名；去除where条件查询所有的表信息
order by
a.id,a.colorder
MySql
查询表的所有字段名：
select *
from information_schema.columns
where table_name=\'table_name\'
and table_schema=\'table_schema\'
ORDER BY ORDINAL_POSITION
ACCESS
查看所有表名：
select name from MSysObjects where type=1 and flags=0
MSysObjects是系统对象，默认情况是隐藏的。通过工具、选项、视图、显示、系统对象可以使之显示出来。
Oracle
select cname from col where tname=\'ZW_YINGYEZ\'
select column_name from user_tab_columns where table_name=\'ZW_YINGYEZ\'
查询表字段数
select count(column_name) from user_tab_columns where table_name=\'表名\';