開發中經常用到查詢指定表及其字段的信息，以下是我整理的SQL語句查詢方法，供自己平時使用也提供給大家參考！

1.適用MS SQL SERVER:

 1 SELECT 2 表名 = case when a.colorder=1 then d.name else '' end, 3 表說明 = case when a.colorder=1 then isnull(f.value,'') else '' end, 4 字段序號 = a.colorder, 5 字段名 = a.name, 6 標識 = case when COLUMNPROPERTY( a.id,a.name,'IsIdentity')=1 then '√'else '' end, 7 主鍵 = 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 類型 = b.name,11 占用字節數 = a.length,12 長度 = COLUMNPROPERTY(a.id,a.name,'PRECISION'),13 小數位數 = isnull(COLUMNPROPERTY(a.id,a.name,'Scale'),0),14 允許空 = case when a.isnullable=1 then '√'else '' end,15 默認值 = isnull(e.text,''),16 字段說明 = isnull(g.[value],'')17 FROM18 syscolumns a19 left join20 systypes b21 on22 a.xusertype=b.xusertype23 inner join24 sysobjects d25 on26 a.id=d.id and d.xtype='U' and d.name<>'dtproperties'27 left join28 syscomments e29 on30 a.cdefault=e.id31 left join32 sys.extended_properties g33 on34 --a.id=g.id and a.colid=g.smallid35 a.id=g.major_id and a.colid=g.Minor_id36 left join37 sys.extended_properties f38 on39 --d.id=f.id and f.smallid=040 d.id=f.major_id and f.Minor_id=041 where42 d.name='表名' --如果只查詢指定表,加上此條件43 order by44 a.id,a.colorder

2.適用Oracle:

 1 SELECT 2 USER_TAB_COLS.TABLE_NAME as 表名, 3 user_tab_comments.comments as 表備注, 4 USER_TAB_COLS.COLUMN_ID as 列序號, 5 user_col_comments.comments as 列備注, 6 USER_TAB_COLS.COLUMN_NAME as 列名 , 7 USER_TAB_COLS.DATA_TYPE as 數據類型, 8 USER_TAB_COLS.DATA_LENGTH as 長度, 9 USER_TAB_COLS.NULLABLE as 是否為空,10 user_cons_columns.constraint_name as 約束名,11 user_constraints.constraint_type as 主鍵12 FROM USER_TAB_COLS inner join user_col_comments on13 user_col_comments.TABLE_NAME=USER_TAB_COLS.TABLE_NAME14 and user_col_comments.COLUMN_NAME=USER_TAB_COLS.COLUMN_NAME15 INNER join user_cons_columns on user_cons_columns.table_name=USER_TAB_COLS.table_name16 INNER join user_constraints on user_constraints.table_name=USER_TAB_COLS.table_name and user_constraints.constraint_name=user_cons_columns.constraint_name17 inner join user_tab_comments on USER_TAB_COLS.TABLE_NAME=user_tab_comments.TABLE_NAME18 WHERE USER_TAB_COLS.table_name='表名'19 ORDER BY USER_TAB_COLS.TABLE_NAME

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