--Type
CREATE OR REPLACE TYPE zh_concat_im AUTHID CURRENT_USER AS OBJECT
(
CURR_STR clob,
STATIC FUNCTION ODCIAGGREGATEINITIALIZE(SCTX IN OUT zh_concat_im)
RETURN NUMBER,
MEMBER FUNCTION ODCIAGGREGATEITERATE(SELF IN OUT zh_concat_im,
P1 IN VARCHAR2) RETURN NUMBER,
MEMBER FUNCTION ODCIAGGREGATETERMINATE(SELF IN zh_concat_im,
RETURNVALUE OUT clob,
FLAGS IN NUMBER)
RETURN NUMBER,
MEMBER FUNCTION ODCIAGGREGATEMERGE(SELF IN OUT zh_concat_im,
SCTX2 IN zh_concat_im) RETURN NUMBER
); --TYPE BODY
CREATE OR REPLACE TYPE BODY zh_concat_im IS
STATIC FUNCTION ODCIAGGREGATEINITIALIZE(SCTX IN OUT zh_concat_im)
RETURN NUMBER IS
BEGIN
SCTX := zh_concat_im(NULL);
RETURN ODCICONST.SUCCESS;
END;
MEMBER FUNCTION ODCIAGGREGATEITERATE(SELF IN OUT zh_concat_im,
P1 IN VARCHAR2) RETURN NUMBER IS
BEGIN
IF (CURR_STR IS NOT NULL) THEN
CURR_STR := CURR_STR || ',' || P1;
ELSE
CURR_STR := P1;
END IF;
RETURN ODCICONST.SUCCESS;
END;
MEMBER FUNCTION ODCIAGGREGATETERMINATE(SELF IN zh_concat_im,
RETURNVALUE OUT clob,
FLAGS IN NUMBER) RETURN NUMBER IS
BEGIN
RETURNVALUE := CURR_STR;
RETURN ODCICONST.SUCCESS;
END;
MEMBER FUNCTION ODCIAGGREGATEMERGE(SELF IN OUT zh_concat_im,
SCTX2 IN zh_concat_im) RETURN NUMBER IS
BEGIN
IF (SCTX2.CURR_STR IS NOT NULL) THEN
SELF.CURR_STR := SELF.CURR_STR || ',' || SCTX2.CURR_STR;
END IF;
RETURN ODCICONST.SUCCESS;
END;
END; --FUNCTION
create or replace FUNCTION zh_concat(P1 VARCHAR2) RETURN clob AGGREGATE USING zh_concat_im;
首先创建一个Type，一个Type Body，最后利用该Type和Type Body 创建一个返回类型为Clob的function,返回的结果是中间用逗号隔开的clob字段，如下图所示：
select zh_concat(distinct(t.standardsort)) standardsort from TB_SD_STANDARD_CHOOSE_ADVISE t
结果如下：
在后台操作获取该clob字段的内容如以下代码所示：
BufferedReader in = null;
StringWriter out = null;
String content = "";
try {
Clob clob = (Clob)objs[5];
in = new BufferedReader(clob.getCharacterStream());
out = new StringWriter();
int c;
while ((c = in.read()) != -1) {
out.write(c);
}
content = out.toString();
} catch (Exception e) {
e.printStackTrace();
} finally {
in.close();
out.close();
}