代码为：
- SQL code
SELECT NULL "COLUMN_ID", NULL "COLUMN_NAME", NULL "COLUMN_TYPE", NULL "LENGTH", NULL "DATA_DEFAULT", NULL "NULL", NULL "PK", TABLE_NAMEFROM USER_TAB_COLUMNSUNION SELECT COLUMN_ID,UT.COLUMN_NAME,DATA_TYPE,CHAR_LENGTH,long_to_varchar2(UT.TABLE_NAME,UT.COLUMN_NAME,'DATA_DEFAULT','USER_TAB_COLUMNS',USER)"DATA_DEFAULT",NULLABLE,DECODE(UT.COLUMN_NAME,CS.COLUMN_NAME,'Y','N') "IS_PAR_KEY",UT.TABLE_NAMEFROM USER_TAB_COLUMNS UT, ( SELECT UC.TABLE_NAME, UCS.COLUMN_NAME FROM USER_CONSTRAINTS UC, USER_CONS_COLUMNS UCS WHERE UC.TABLE_NAME = UCS.TABLE_NAME AND UC.CONSTRAINT_NAME = UCS.CONSTRAINT_NAME AND UC.CONSTRAINT_TYPE = 'P' )CSWHERE UT.TABLE_NAME = CS.TABLE_NAME(+)ORDER BY TABLE_NAME,1 ASC;
重复部分：
1 VC_CALLINGNUM VARCHAR2 21 N N TB_RT_ROUTEPOLICY
1 VC_CALLINGNUM VARCHAR2 21 N Y TB_RT_ROUTEPOLICY
2 VC_CUSTOMER VARCHAR2 21 N N TB_RT_ROUTEPOLICY
2 VC_CUSTOMER VARCHAR2 21 N Y TB_RT_ROUTEPOLICY
3 VC_PREFIXCODE VARCHAR2 21 N N TB_RT_ROUTEPOLICY
3 VC_PREFIXCODE VARCHAR2 21 N Y TB_RT_ROUTEPOLICY
4 INT_INTERVALID NUMBER 0 N N TB_RT_ROUTEPOLICY
4 INT_INTERVALID NUMBER 0 N Y TB_RT_ROUTEPOLICY
5 INT_ROUTEID NUMBER 0 N N TB_RT_ROUTEPOLICY
5 INT_ROUTEID NUMBER 0 N Y TB_RT_ROUTEPOLICY
6 INT_DAYOFWEEK NUMBER 0 N N TB_RT_ROUTEPOLICY
6 INT_DAYOFWEEK NUMBER 0 N Y TB_RT_ROUTEPOLICY
7 INT_TRAFFICASSIGNMODE NUMBER 0 N N TB_RT_ROUTEPOLICY
重复的不是很多，我手动删除了，但是不知道为什么会重复。
------解决方案--------------------
你UNION前后都用了USER_TAB_COLUMNS这表
相当于两次查询，
然后第一遍许多字段都人为置成null了，本身用union会滤去重复的，但你置成了null，就不是重复的了
------解决方案--------------------
对不起，用一下下面的语句再试试：
SELECT distinct nvl("COLUMN_ID",0),
"COLUMN_NAME",
"COLUMN_TYPE",
"LENGTH",
"DATA_DEFAULT",
"NULL",
"PK",
TABLE_NAME
FROM USER_TAB_COLUMNS
UNION SELECT distinct COLUMN_ID,
UT.COLUMN_NAME,
DATA_TYPE,
CHAR_LENGTH,
long_to_varchar2(UT.TABLE_NAME,UT.COLUMN_NAME,'DATA_DEFAULT','USER_TAB_COLUMNS',USER)"DATA_DEFAULT",
NULLABLE,
DECODE(UT.COLUMN_NAME,
CS.COLUMN_NAME,'Y','N') "IS_PAR_KEY",
UT.TABLE_NAME
FROM USER_TAB_COLUMNS UT,
(
SELECT UC.TABLE_NAME,
UCS.COLUMN_NAME
FROM USER_CONSTRAINTS UC,
USER_CONS_COLUMNS UCS
WHERE UC.TABLE_NAME = UCS.TABLE_NAME
AND UC.CONSTRAINT_NAME = UCS.CONSTRAINT_NAME
AND UC.CONSTRAINT_TYPE = 'P'
)CS
WHERE UT.TABLE_NAME = CS.TABLE_NAME(+)
ORDER BY TABLE_NAME,1 ASC;
------解决方案--------------------
换成下面这个试试看，如果有问题发消息给我：
- SQL code
SELECT NULL "COLUMN_ID", NULL "COLUMN_NAME", NULL "COLUMN_TYPE", NULL "LENGTH", NULL "DATA_DEFAULT", NULL "NULL", NULL "PK", TABLE_NAME FROM USER_TAB_COLUMNSUNION SELECT COLUMN_ID, UT.COLUMN_NAME, DATA_TYPE, CHAR_LENGTH, LONG_TO_VARCHAR2(UT.TABLE_NAME, UT.COLUMN_NAME, 'DATA_DEFAULT', 'USER_TAB_COLUMNS', USER) "DATA_DEFAULT", NULLABLE, DECODE(UT.COLUMN_NAME, CS.COLUMN_NAME, 'Y', 'N') "IS_PAR_KEY", UT.TABLE_NAME FROM USER_TAB_COLUMNS UT, (SELECT UC.TABLE_NAME, UCS.COLUMN_NAME FROM USER_CONSTRAINTS UC, USER_CONS_COLUMNS UCS WHERE UC.TABLE_NAME = UCS.TABLE_NAME AND UC.CONSTRAINT_NAME = UCS.CONSTRAINT_NAME AND UC.CONSTRAINT_TYPE = 'P') CS WHERE UT.TABLE_NAME = CS.TABLE_NAME(+) AND UT.COLUMN_NAME = CS.COLUMN_NAME(+) ORDER BY TABLE_NAME, 1 ASC;