JAVA与ORACLE
JAVA与ORACLE
1、 在JDBC用xsu将SELECT转化为xml(cursor)
2、在数据库中，访问xml数据服务
3、ORACLE JDBC扩展
4、java过程察看跟踪文件
5、用WMSYS.WM_CONCAT进行字符累计运算
一、用ORACLE 的XSU JAVA包将SELECT 查询结果转化为XML数据文件。
该包的名称为xsu.jar，在数据库安装后，可以在安装目录中找到它。
package xmls.com;
importjava.sql.*;
importoracle.xml.sql.query.OracleXMLQuery;
public class testXSU {
public static void main(String[] args) {
try {
Connection myConnection = getConnection("scott","tiger");
myConnection.setAutoCommit(false);
//普通select 测试
// String strSQL="SELECTd.DEPTNO,d.DNAME,d.LOC," +
// "EMPNO,ENAME,JOB,MGR,to_char(HIREDATE,'yyyymmdd') HIREDATE ,"+
// "SAL,nvl(COMM,0)comm from dept d, emp e where d.deptno=e.deptno and d.deptno = 10";
//通过
// 包含cursor 函数的select
String strSQL =
"selectd.deptno,d.dname,d.loc, " +
"cursor(selectempno,ename,job,mgr,hiredate from emp where d.deptno=deptno) emp from dept d where d.deptno >0";
//通过
//2输出方法
OracleXMLQuery qry = new OracleXMLQuery(myConnection, strSQL);
qry.keepObjectOpen(true);
qry.setRowsetTag("DEPTS"); //定义根节点的名称
qry.setRowTag("DEPT"); //定义行名称
//cursor的节点名称 采用了select 中的别名
qry.setDateFormat("yyyy年mm月dd日") //定义date的输出格式;
qry.setMaxRows(2);
qry.setEncoding("UTF-8"); //定义字符
String str =qry.getXMLString();
System.out.println(str);
// XMLDocument domDoc = (XMLDocument)qry.getXMLDOM();
// StringWriter s = newStringWriter(10000);
// domDoc.print(newPrintWriter(s));
// System.out.println(" The string version --->\n"+s.toString());
qry.close();
myConnection.close();
} catch (SQLException e) {
System.out.println("错误代码 = " + e.getErrorCode());
System.out.println("错误信息 = " + e.getMessage());
System.out.println("sql状态 = " + e.getSQLState());
e.printStackTrace();
} //catch (IOException e) {
// System.out.println(e.toString());
// }
}
private static Connection getConnection(String username,
String password) throws SQLException {
DriverManager.registerDriver(new oracle.jdbc.OracleDriver());
Connection conn =
DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl",
username, password);
return conn;
}
}
输出结果
<?xml version= '1.0' encoding = 'UTF-8'?>
<DEPTS>
<DEPT num="1">
<DEPTNO>10</DEPTNO>
<DNAME>ACCOUNTING</DNAME>
<LOC>NEW YORK</LOC>
<EMP>
<EMP_ROW num="1">
<EMPNO>7782</EMPNO>
<ENAME>CLARK</ENAME>
<JOB>MANAGER</JOB>
<MGR>7839</MGR>
<HIREDATE>1981年00月09日</HIREDATE>
</EMP_ROW>
<EMP_ROW num="2">
<EMPNO>7839</EMPNO>
<ENAME>KING</ENAME>
<JOB>PRESIDENT</JOB>
<HIREDATE>1981年00月17日</HIREDATE>
</EMP_ROW>
<EMP_ROW num="3">
<EMPNO>7934</EMPNO>
<ENAME>MILLER</ENAME>
<JOB>CLERK</JOB>
<MGR>7782</MGR>
<HIREDATE>1982年00月23日</HIREDATE>
</EMP_ROW>
</EMP>
</DEPT>
<DEPT num="2">
<DEPTNO>20</DEPTNO>
<DNAME>RESEARCH</DNAME>
<LOC>DALLAS</LOC>
<EMP>
<EMP_ROW num="1">
<EMPNO>7369</EMPNO>
<ENAME>SMITH</ENAME>
<JOB>CLERK</JOB>
<MGR>7902</MGR>
<HIREDATE>1980年00月17日</HIREDATE>
</EMP_ROW>
<EMP_ROW num="2">
<EMPNO>7566</EMPNO>
<ENAME>JONES</ENAME>
<JOB>MANAGER</JOB>
<MGR>7839</MGR>
<HIREDATE>1981年00月02日</HIREDATE>
</EMP_ROW>
<EMP_ROW num="3">
<EMPNO>7788</EMPNO>
<ENAME>SCOTT</ENAME>
<JOB>ANALYST</JOB>
<MGR>7566</MGR>
<HIREDATE>1987年00月19日</HIREDATE>
</EMP_ROW>
<EMP_ROW num="4">
<EMPNO>7876</EMPNO>
<ENAME>ADAMS</ENAME>
<JOB>CLERK</JOB>
<MGR>7788</MGR>
<HIREDATE>1987年00月23日</HIREDATE>
</EMP_ROW>
<EMP_ROW num="5">
<EMPNO>7902</EMPNO>
<ENAME>FORD</ENAME>
<JOB>ANALYST</JOB>
<MGR>7566</MGR>
<HIREDATE>1981年00月03日</HIREDATE>
</EMP_ROW>
</EMP>
</DEPT>
</DEPTS>
二、在数据中访问xml数据服务
观察来自以下的数据服务
http://asktom.oracle.com/pls/ask/ask_tom.newest.rss
以下的代码，可以在oracle数据库中取得该数据
create table c_clob
(y clob,
x xmltype
)
declare
l_url httpuritype;
l_xml xmltype;
l_len integer;
clob_1 clob;
l_rss_version number;
begin
l_url:= httpuritype.createuri('http://asktom.oracle.com/pls/ask/ask_tom.newest.rss');
l_xml:= l_url.getxml();
clob_1:= l_xml.extract('/').getstringval();
l_len:= length(l_xml.extract('/').getstringval());
insert intoc_clob(y,x) values(clob_1, l_xml);
commit;
dbms_output.put_line(l_len);
--dbms_output.put_line(substr(l_xml.extract('/').getstringval(),1,250));
l_rss_version := l_xml.extract('/rss/@version').getNumberVal();
dbms_output.put_line(l_rss_version);
end;
遗留问题：
1、11g个中增加了安全机制，在普通用户下运行上述需要手工配置ACL ;
2、利用createuri下的其他函数可以取得网页数据，邮件数据。
在return的后面的语句不会被执行
create table t
(
a varchar2(10)
)
create or replace function foo(val1varchar2) return varchar2 as
begin
insert into t values ('hh');
dbms_lock.sleep(5);
return val1 || 'suffix';
insert into t values ('hh');
end;
declare
iinteger;
avarchar2(10);
begin
--Test statements here
a:=foo('hhhh');
dbms_output.put_line(a);
select count(*) into i from t;
dbms_output.put_line(i);
end;
文打印出的i是多少？
package yourcompany.yourapp.model.custom;
import java.sql.*;
import oracle.jdbc.*;
import oracle.jdbc.pool.OracleDataSource;
import java.io.*;
public class TestProc
{
public static void main(String args[])throws SQLException, IOException
{
// Prompt the user for connect information
System.out.println("Please enterinformation to test connection to the database");
String user="scott";
String password="tiger";
Stringdatabase="localhost:1521:gq";
System.out.flush();
System.out.println("Connecting...");
// Open an OracleDataSource and get aconnection
OracleDataSource ods = newOracleDataSource();
ods.setURL("jdbc:oracle:thin:@" +database);
ods.setUser(user);
ods.setPassword(password);
Connection conn = ods.getConnection();
conn.setAutoCommit(false);
System.out.println("connected.");
// Create a statement
CallableStatement cs = conn.prepareCall("begin ? := foo(?); end;");
cs.registerOutParameter(1,Types.CHAR);
cs.setString(2, "aa");
cs.executeUpdate();
String result = cs.getString(1);
cs.close();
Statement stmt = conn.createStatement();
ResultSet rset =stmt.executeQuery("select a from t");
while (rset.next())
System.out.println(rset.getString(1));
conn.rollback();
rset.close();
stmt.close();
conn.close();
System.out.println(result);
System.out.println("Your JDBCinstallation is correct.");
}
}
如果没有conn.rollback(); 数据是否被提交？
三、使用oracle的jabc的扩展
package mycompany.guanqi.j;
import java.sql.*;
import oracle.sql.*;
import oracle.jdbc.*;
public class BasicExample3 {
public static void main(String[] args) {
try {
DriverManager.registerDriver(new oracle.jdbc.OracleDriver());
Connection myConnection =
DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:GQ",
"scott","tiger");
myConnection.setAutoCommit(false);
oracle.sql.NUMBER customerId = new oracle.sql.NUMBER(6);
int customerIdInt = customerId.intValue();
System.out.println("customerIdInt = " + customerIdInt);
oracle.sql.CharacterSet myCharSet =
CharacterSet.make(CharacterSet.US7ASCII_CHARSET);
oracle.sql.CHAR firstName =
neworacle.sql.CHAR("Jason", myCharSet);
String firstNameString =firstName.stringValue();
System.out.println("firstNameString = " + firstNameString);
oracle.sql.CHAR lastName = new oracle.sql.CHAR("Price",myCharSet);
System.out.println("lastName = " + lastName);
oracle.sql.DATE dob = new oracle.sql.DATE("1969-02-22 13:54:12");
String dobString = dob.stringValue();
System.out.println("dobString = " + dobString);
OraclePreparedStatementmyPrepStatement =
(OraclePreparedStatement)myConnection.prepareStatement("INSERTINTO t VALUES (?)");
myPrepStatement.setCHAR(1, firstName);
myPrepStatement.execute();
myPrepStatement.close();
System.out.println("Added row to customers table");
Statement myStatement = myConnection.createStatement();
OracleResultSet customerResultSet =
(OracleResultSet)myStatement.executeQuery("SELECT ROWID r, a FROM t");
System.out.println("Retrieved row from customers table");
oracle.sql.ROWID rowid;
oracle.sql.CHAR pa = new oracle.sql.CHAR("", myCharSet);
OraclePreparedStatement pstmt =
(OraclePreparedStatement)myConnection.prepareStatement("UPDATEt SET a = ? WHERE rowid = CHARTOROWID(?)");
while (customerResultSet.next()) {
rowid =customerResultSet.getROWID("r");
pa =customerResultSet.getCHAR("a");
String s1=pa.stringValue()+"aaaa";
oracle.sql.CHAR newpa = new oracle.sql.CHAR(s1, myCharSet);
System.out.println("rowid= " + rowid.stringValue()+"
"+newpa.stringValue());
pstmt.setCHAR (1, newpa);
pstmt.setROWID (2, rowid);
pstmt.executeUpdate ();
}
pstmt.close();
customerResultSet.close();
myConnection.commit();
myConnection.close();
} catch (SQLException e) {
System.out.println("错误代码 = " + e.getErrorCode());
System.out.println("错误信息 = " + e.getMessage());
System.out.println("sql状态 = " + e.getSQLState());
e.printStackTrace();
}
}
}
采用oracle jdbc扩展，可以处理oracle的繁多的数据类型，如对象类型，对象类型等，从而提高程序效率。
如：
create or replace type p_in is table of number
create or replace procedure procin(p1 in p_in) is
i integer;
begin
i:=p1.count;
for k in 1..i loop
insert into t values(p1(k));
end loop;
end procin;
package mycompany.guanqi.j;
import java.sql.*;
import oracle.sql.*;
import oracle.jdbc.*;
import oracle.jdbc.pool.OracleDataSource;
public class Test_col {
public static void main(String[] args) {
try {
OracleDataSource ods = new OracleDataSource();
ods.setURL("jdbc:oracle:thin:@localhost:1521:gq");
ods.setUser("scott");
ods.setPassword("tiger");
Connectionconn = ods.getConnection();
conn.setAutoCommit(false);
System.out.println("connected.");
OracleCallableStatement procin =(OracleCallableStatement)conn.prepareCall ("begin procin (?); end;");
int[]values = { 1, 2, 3 };
ARRAY ary1 = newARRAY(ArrayDescriptor.createDescriptor("P_IN", conn), conn, values);
procin.setObject(1, ary1,OracleTypes.ARRAY);
procin.execute ();
System.out.println("执行成功");
procin.close();
conn.commit();
conn.close();
}
catch (SQLException e) {
System.out.println("错误代码 = " + e.getErrorCode());
System.out.println("错误信息 = " + e.getMessage());
System.out.println("sql状态 = " + e.getSQLState());
e.printStackTrace();
}
}
}
package mycompany.guanqi.j;
import java.sql.*;
import oracle.sql.*;
import oracle.jdbc.*;
import oracle.jdbc.pool.OracleDataSource;
public class TestRowid_ora {
public static void main(String[] args) {
try {
OracleDataSource ods = new OracleDataSource();
ods.setURL("jdbc:oracle:thin:@localhost:1521:gq");
ods.setUser("scott");
ods.setPassword("tiger");
Connection conn = ods.getConnection();
conn.setAutoCommit(false);
System.out.println("connected.");
oracle.sql.CharacterSet myCharSet = CharacterSet.make(CharacterSet.ZHS16GBK_CHARSET);
oracle.sql.CHAR mystr = new oracle.sql.CHAR("中华sss", myCharSet);
System.out.println(mystr.stringValue());
OraclePreparedStatementmyPrepStatement =
(OraclePreparedStatement)conn.prepareStatement("INSERTINTO t VALUES (?)");
myPrepStatement.setCHAR(1, mystr);
myPrepStatement.execute();
myPrepStatement.close();
System.out.println("增加一行数据");
conn.commit();
conn.close();
}
catch (SQLException e) {
System.out.println("错误代码 = " + e.getErrorCode());
System.out.println("错误信息 = " + e.getMessage());
System.out.println("sql状态 = " + e.getSQLState());
e.printStackTrace();
}
}
}
在JDBC中使用集合操作方法
建立集合类型
create type P_IN is table of number
建立一个使用集合的过程
create or replace procedure procin(p1 inp_in) is
i integer;
begin
i:=p1.count;
for k in 1..i loop
insert into t values(p1(k));
end loop;
end procin;
JDBC程序
package mycompany.guanqi.j;
import java.sql.*;
import oracle.sql.*;
import oracle.jdbc.*;
import oracle.jdbc.pool.OracleDataSource;
public class Test_col {
public static void main(String[] args) {
try {
OracleDataSource ods = new OracleDataSource();
ods.setURL("jdbc:oracle:thin:@localhost:1521:gq");
ods.setUser("scott");
ods.setPassword("tiger");
Connection conn = ods.getConnection();
conn.setAutoCommit(false);
System.out.println("connected.");
OracleCallableStatement procin =(OracleCallableStatement)conn.prepareCall ("begin procin (?); end;");
int[] values = { 1, 2, 3 };
ARRAY ary1 = newARRAY(ArrayDescriptor.createDescriptor("P_IN", conn), conn, values);
procin.setObject(1, ary1, OracleTypes.ARRAY);
procin.execute ();
System.out.println("执行成功");
procin.close();
conn.commit();
conn.close();
}
catch (SQLException e) {
System.out.println("错误代码 = " + e.getErrorCode());
System.out.println("错误信息 = " + e.getMessage());
System.out.println("sql状态 = " + e.getSQLState());
e.printStackTrace();
}
}
}
四、java过程察看跟踪文件
nvl问题
package mycompany.guanqi.j;
import java.sql.*;
import oracle.jdbc.pool.OracleDataSource;
import java.io.*;
import oracle.jdbc.OracleTypes;
class nvl_test {
public static void main(String[] args) throws SQLException, IOException{
String user = "scott";
String password = "tiger";
String database = "localhost:1521:gq";
System.out.println("Connecting...");
// Open an OracleDataSource and get a connection
OracleDataSource ods = new OracleDataSource();
ods.setURL("jdbc:oracle:thin:@" + database);
ods.setUser(user);
ods.setPassword(password);
Connection conn = ods.getConnection();
System.out.println("connected.");
PreparedStatement pstmt = null;
try{
pstmt = conn.prepareStatement ("select count(distinct d.dname) fromdept d where d.deptno=nvl(?,d.deptno)");
pstmt.setInt (1, 11); //假定一个不存在的deptno
//pstmt.setInt (1, 10); //假定一个存在的deptno
//pstmt.setNull(1,OracleTypes.NUMERIC); //假定没有输入参数
ResultSet rset = pstmt.executeQuery();
while (rset.next())
System.out.println(rset.getString(1));
rset.close();
}
finally{
if(pstmt!=null)
// Close the statement
pstmt.close();
}
conn.close();
System.out.println("test is finished");
}
}
看看后台发生了什么
比较以下过程
declare
-- Local variables here
i integer;
i_count integer;
begin
select count(*) into i_count from dept dwhere d.deptno= nvl(i,d.deptno);
dbms_output.put_line(i_count);
end;
看看后台发生了什么？对于DML语句，我们可以有以下方法观察：
1、 mv_log
2、 编写触发器
3、 logminer
4、 跟踪文件
5、 V$sql_text表
但是对于select语句，由于select不产生log（产生log的情况很少，如块清除），只能用一下方法来看
1、V$sql_text表
2、跟踪文件
取得跟踪文件名的方法
1、 为了简化java程序建立一个视图,取得当前跟踪文件名
2、 create view v_tkprof
as
select p1.value||'\'||p2.value||'_ora_'||p.spid||'.trc' filename
from
v$process p,
v$session s,
v$parameter p1,
v$parameter p2
where p1.name = 'user_dump_dest'
and p2.name = 'db_name'
and p.addr = s.paddr
and s.audsid = userenv ('sessionid')
如果当前没有权限浏览上述视图中的系统表，首先用dba帐号进行授权。
tkprof d:\app\gx\diag\rdbms\gq\gq\trace\gq_ora_5880.trcd:\app\gx\diag\rdbms\gq\gq\trace\gq_ora_5880.txt
java程序
import java.sql.*;
import oracle.sql.*;
import oracle.jdbc.*;
import oracle.xml.sql.query.OracleXMLQuery;
public class jdbc_tkprof {
public static voidmain(String[] args) {
try {
Connection myConnection =getConnection("scott","tiger");
myConnection.setAutoCommit(false);
Statement stmt =myConnection.createStatement();
String cmd;
cmd = "altersession set sql_trace = true";
stmt.execute(cmd);
cmd = "alter session set timed_statistics = true";
stmt.execute(cmd);
cmd = "alter sessionset events '10046 trace name context forever,level 12'";
stmt.execute(cmd);
cmd = "altersession setmax_dump_file_size=unlimited";
stmt.execute(cmd);
// cmd = "altersession set events '10046 trace namecontext off'";
// stmt.execute(cmd);
StringstrSQL="select filename from v_tkprof" ;
ResultSet rs =stmt.executeQuery(strSQL);
while (rs.next())
System.out.println(rs.getString(1));
rs.close();
stmt.close();
PreparedStatement stmt1 =null;
try{
stmt1 =myConnection.prepareStatement ("select count(distinct d.dname) from dept dwhere d.deptno=nvl(?,d.deptno)");
//stmt1.setInt (1,11); //假定一个不存在的deptno
//stmt1.setInt (1,10); //假定一个存在的deptno
stmt1.setNull(1,OracleTypes.NUMERIC); //假定没有输入参数
ResultSet rset =stmt1.executeQuery();
while(rset.next())
System.out.println(rset.getString(1));
rset.close();
}
finally{
if(stmt1!=null)
stmt1.close();
}
myConnection.close();
} catch (SQLException e) {
System.out.println("错误代码 = " +e.getErrorCode());
System.out.println("错误信息 = " +e.getMessage());
System.out.println("sql状态 = " +e.getSQLState());
e.printStackTrace();
} //catch (IOException e) {
// System.out.println(e.toString());
// }
}
private static ConnectiongetConnection(String username, String password)
throws SQLException
{
DriverManager.registerDriver(new oracle.jdbc.OracleDriver());
Connection conn =
DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:GQ",username,password);
return conn;
}
}
我们尝试运行上述程序，发现每一次跟踪文件名称不一样
观察对程序中sql的运行情况
SQL ID : 8c1a6t15jh7n0
select count(distinct d.dname)
from
deptd where d.deptno=nvl(:1,d.deptno)
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.01 0 0 0 0
Fetch 1 0.00 0.01 0 3 0 1
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 3 0.00 0.03 0 3 0 1
Misses inlibrary cache during parse: 1
Misses in library cache during execute: 1
Optimizer mode: ALL_ROWS
Parsing user id: 81
Rows RowSource Operation
------- ---------------------------------------------------
1 SORT GROUP BY (cr=3 pr=0 pw=0 time=0 us)
5 CONCATENATION (cr=3 pr=0 pw=0 time=14 us)
5 FILTER (cr=3 pr=0 pw=0 time=10 us)
5 TABLE ACCESS BY INDEX ROWID DEPT (cr=3pr=0 pw=0 time=6 us cost=3 size=55 card=5)
5 INDEX FULL SCAN PK_DEPT (cr=1 pr=0 pw=0time=2 us cost=1 size=0 card=5)(object id 69538)
0 FILTER (cr=0 pr=0 pw=0 time=0 us)
0 TABLE ACCESS BY INDEX ROWID DEPT (cr=0pr=0 pw=0 time=0 us cost=1 size=11 card=1)
0 INDEX UNIQUE SCAN PK_DEPT (cr=0 pr=0 pw=0time=0 us cost=0 size=0 card=1)(object id 69538)
SQL ID :8c1a6t15jh7n0
8c1a6t15jh7n0（上一次的sqlid）
select count(distinct d.dname)
from
dept d whered.deptno=nvl(:1,d.deptno)
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 1 0.00 0.00 0 3 0 1
------- ------ ------------------ ---------- ---------- ---------- ----------
total 3 0.00 0.00 0 3 0 1
Misses inlibrary cache during parse: 0
Optimizer mode: ALL_ROWS
Parsing user id: 81
Rows RowSource Operation
------- ---------------------------------------------------
1 SORT GROUP BY (cr=3 pr=0 pw=0 time=0 us)
5 CONCATENATION (cr=3 pr=0 pw=0 time=14 us)
5 FILTER (cr=3 pr=0 pw=0 time=10 us)
5 TABLE ACCESS BY INDEX ROWID DEPT (cr=3pr=0 pw=0 time=6 us cost=3 size=55 card=5)
5 INDEX FULL SCAN PK_DEPT (cr=1 pr=0 pw=0time=2 us cost=1 size=0 card=5)(object id 69538)
0 FILTER (cr=0 pr=0 pw=0 time=0 us)
0 TABLE ACCESS BY INDEX ROWID DEPT (cr=0 pr=0pw=0 time=0 us cost=1 size=11 card=1)
0 INDEX UNIQUE SCAN PK_DEPT (cr=0 pr=0 pw=0time=0 us cost=0 size=0 card=1)(object id 69538)
Elapsed times include waiting on following events:
Event waitedon Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net messageto client 2 0.00 0.00
SQL*Net messagefrom client 2 0.02 0.04
********************************************************************************
与在数据库中对下列sql的执行计划很相似
select count(distinct d.dname)
from dept d
where d.deptno=nvl(:1,d.deptno)
我们传递了一个null的参数，发现这个执行计划有什么问题？
不应该存在索引扫描，而应该是直接的全表扫描。
如何解决这个问题呢？
五、用WMSYS.WM_CONCAT进行字符累计运算
这个特性只有在10g以后的版本中提供
select version from v$instance;
VERSION
-----------------
10.2.0.1.0
create table test_char_agg
(
idnumber,
val varchar2(20) );
Table created
insert into test_char_agg (ID, VAL) values (10, 'abc');
insert into test_char_agg (ID, VAL) values (10, 'abc');
insert into test_char_agg (ID, VAL) values (10, 'def');
insert into test_char_agg (ID, VAL) values (10, 'def');
insert into test_char_agg (ID, VAL) values (20, 'ghi');
insert into test_char_agg (ID, VAL) values (20, 'jkl');
insert into test_char_agg (ID, VAL) values (20, 'mno');
insert into test_char_agg (ID, VAL) values (20, 'mno');
select id,val from test_char_agg;
ID VAL
------------------------------
10 abc
10 abc
10 def
10 def
20 ghi
20 jkl
20 mno
20 mno
SELECT ID, WMSYS.WM_CONCAT(VAL) ASENAMES FROM test_char_agg GROUP BY ID;
ID ENAMES
------------------------------------------------------------------------------------------
10 abc,abc,def,def
20 ghi,jkl,mno,mno
SELECT ID,WMSYS.WM_CONCAT(DISTINCT VAL) AS ENAMES
FROM test_char_agg
GROUP BY ID
ORDER BY ID;
ID ENAMES
------------------------------------------------------------------------------------------
10 abc,def
20 ghi,jkl,mno
SELECT ID, VAL,WMSYS.WM_CONCAT(VAL) OVER(PARTITION BY ID) AS ENAMES
FROMtest_char_agg
ORDER BY ID;
ID VAL ENAMES
---------- ----------------------------------------------------------------------------------------------------
10 abc abc,abc,def,def
10 abc abc,abc,def,def
10 def abc,abc,def,def
10 def abc,abc,def,def
20 ghi ghi,jkl,mno,mno
20 jkl ghi,jkl,mno,mno
20 mno ghi,jkl,mno,mno
20 mno ghi,jkl,mno,mno
SELECT ID, VAL,WMSYS.WM_CONCAT(VAL) OVER(ORDER BY ID, VAL) AS ENAMES
FROMtest_char_agg
ORDER BY ID;
ID VAL ENAMES
---------- ----------------------------------------------------------------------------------------------------
10 abc abc,abc
10 abc abc,abc
10 def abc,abc,def,def
10 def abc,abc,def,def
20 ghi abc,abc,def,def,ghi
20 jkl abc,abc,def,def,ghi,jkl
20 mno abc,abc,def,def,ghi,jkl,mno,mno
20 mno abc,abc,def,def,ghi,jkl,mno,mno
原创文章，如果转载，请标注作者：田文 CSDN地址：http://blog.csdn.net/tiwen818