sql语句查询数据库表结构信息

开发中经常用到查询指定表及其字段的信息，以下是我整理的SQL语句查询方法，供自己平时使用也提供给大家参考！

1.适用MS SQL SERVER:

 1 SELECT
 2 表名 = case when a.colorder=1 then d.name else ‘‘ end,
 3 表说明 = case when a.colorder=1 then isnull(f.value,‘‘) else ‘‘ end,
 4 字段序号 = a.colorder,
 5 字段名 = a.name,
 6 标识 = case when COLUMNPROPERTY( a.id,a.name,‘IsIdentity‘)=1 then ‘√‘else ‘‘ end,
 7 主键 = case when exists(SELECT 1 FROM sysobjects where xtype=‘PK‘ and parent_obj=a.id and name in (
 8 SELECT name FROM sysindexes WHERE indid in(
 9 SELECT indid FROM sysindexkeys WHERE id = a.id AND colid=a.colid))) then ‘√‘ else ‘‘ end,
10 类型 = b.name,
11 占用字节数 = a.length,
12 长度 = COLUMNPROPERTY(a.id,a.name,‘PRECISION‘),
13 小数位数 = isnull(COLUMNPROPERTY(a.id,a.name,‘Scale‘),0),
14 允许空 = case when a.isnullable=1 then ‘√‘else ‘‘ end,
15 默认值 = isnull(e.text,‘‘),
16 字段说明 = isnull(g.[value],‘‘)
17 FROM
18 syscolumns a
19 left join
20 systypes b
21 on
22 a.xusertype=b.xusertype
23 inner join
24 sysobjects d
25 on
26 a.id=d.id and d.xtype=‘U‘ and d.name<>‘dtproperties‘
27 left join
28 syscomments e
29 on
30 a.cdefault=e.id
31 left join
32 sys.extended_properties g
33 on
34 --a.id=g.id and a.colid=g.smallid
35 a.id=g.major_id and a.colid=g.Minor_id
36 left join
37 sys.extended_properties f
38 on
39 --d.id=f.id and f.smallid=0
40 d.id=f.major_id and f.Minor_id=0
41 where
42 d.name=‘表名‘ --如果只查询指定表,加上此条件
43 order by
44 a.id,a.colorder

2.适用ORACLE:

 1 SELECT
 2 USER_TAB_COLS.TABLE_NAME as 表名,
 3 user_tab_comments.comments as 表备注,
 4 USER_TAB_COLS.COLUMN_ID as 列序号,
 5 user_col_comments.comments as 列备注,
 6 USER_TAB_COLS.COLUMN_NAME as 列名 ,
 7 USER_TAB_COLS.DATA_TYPE as 数据类型,
 8 USER_TAB_COLS.DATA_LENGTH as 长度,
 9 USER_TAB_COLS.NULLABLE as 是否为空,
10 user_cons_columns.constraint_name as 约束名,
11 user_constraints.constraint_type as 主键
12 FROM USER_TAB_COLS inner join user_col_comments on
13 user_col_comments.TABLE_NAME=USER_TAB_COLS.TABLE_NAME
14 and user_col_comments.COLUMN_NAME=USER_TAB_COLS.COLUMN_NAME
15 INNER join user_cons_columns on user_cons_columns.table_name=USER_TAB_COLS.table_name
16 INNER join user_constraints on user_constraints.table_name=USER_TAB_COLS.table_name and user_constraints.constraint_name=user_cons_columns.constraint_name
17 inner join user_tab_comments on USER_TAB_COLS.TABLE_NAME=user_tab_comments.TABLE_NAME
18 WHERE USER_TAB_COLS.table_name=‘表名‘
19 ORDER BY USER_TAB_COLS.TABLE_NAME

原文其它网址：http://www.zuowenjun.cn/post/2014/08/28/26.html