这个 fristPinyin 函数是对传入字符串第一个字取拼音缩写字头用的么？不过从给出的GBK编码范围看，貌似只对GB2312的一级汉字区域有效啊，超出部分取得的拼音缩写可能不对。

这个测试OK，可以参考

CREATE OR REPLACE FUNCTION fristPinyin(P_NAME VARCHAR2(255))
RETURN VARCHAR2(255) DETERMINISTIC
IS
  V_RETURN VARCHAR2(255);
  V_BOOL BOOLEAN := FALSE;
  FIRST_VARCHAR VARCHAR2;
  V_HEX VARCHAR2(8);
  V_CODE PLS_INTEGER;
BEGIN
  -- 获取字符串的第一个字符
  FIRST_VARCHAR := SUBSTR(P_NAME, 1, 1);

  -- 检查第一个字符是否为字母
  IF REGEXP_LIKE(FIRST_VARCHAR, '[a-zA-Z]$') THEN
    V_RETURN := FIRST_VARCHAR;
    V_BOOL := TRUE;
  END IF;

  -- 如果不是字母，则根据Unicode码点查找拼音首字母
  IF NOT V_BOOL THEN
      V_HEX := RAWTOHEX(UTL_RAW.CAST_TO_RAW(FIRST_VARCHAR));
      V_CODE := TO_NUMBER(V_HEX, 'XXXX');

	  CASE
		WHEN V_CODE BETWEEN 0xB0A1 AND 0xB0C4 THEN V_RETURN := 'A';
		WHEN V_CODE BETWEEN 0xB0C5 AND 0xB2C0 THEN V_RETURN := 'B';
		WHEN V_CODE BETWEEN 0xB2C1 AND 0xB4EE THEN V_RETURN := 'C';
		WHEN V_CODE BETWEEN 0xB4EF AND 0xB6E9 THEN V_RETURN := 'D';
		WHEN V_CODE BETWEEN 0xB6EA AND 0xB7A1 THEN V_RETURN := 'E';
		WHEN V_CODE BETWEEN 0xB7A2 AND 0xB8BF THEN V_RETURN := 'F';
		WHEN V_CODE BETWEEN 0xB8C0 AND 0xB9FE THEN V_RETURN := 'G';
		WHEN V_CODE BETWEEN 0xB9FF AND 0xBBF6 THEN V_RETURN := 'H';
		WHEN V_CODE BETWEEN 0xBBF7 AND 0xBFA5 THEN V_RETURN := 'J';
		WHEN V_CODE BETWEEN 0xBFA6 AND 0xC0AB THEN V_RETURN := 'K';
		WHEN V_CODE BETWEEN 0xC0AC AND 0xC2E7 THEN V_RETURN := 'L';
		WHEN V_CODE BETWEEN 0xC2E8 AND 0xC4C2 THEN V_RETURN := 'M';
		WHEN V_CODE BETWEEN 0xC4C3 AND 0xC5B5 THEN V_RETURN := 'N';
		WHEN V_CODE BETWEEN 0xC5B6 AND 0xC5BD THEN V_RETURN := 'O';
		WHEN V_CODE BETWEEN 0xC5BE AND 0xC6D9 THEN V_RETURN := 'P';
		WHEN V_CODE BETWEEN 0xC6DA AND 0xC8BA THEN V_RETURN := 'Q';
		WHEN V_CODE BETWEEN 0xC8BB AND 0xC8F5 THEN V_RETURN := 'R';
		WHEN V_CODE BETWEEN 0xC8F6 AND 0xCBF9 THEN V_RETURN := 'S';
		WHEN V_CODE BETWEEN 0xCBFA AND 0xCDD9 THEN V_RETURN := 'T';
		WHEN V_CODE BETWEEN 0xCDDA AND 0xCEF3 THEN V_RETURN := 'W';
		WHEN V_CODE BETWEEN 0xCEF4 AND 0xD1B8 THEN V_RETURN := 'X';
		WHEN V_CODE BETWEEN 0xD1B9 AND 0xD4D0 THEN V_RETURN := 'Y';
		WHEN V_CODE >= 0xD4D1 THEN V_RETURN := 'Z';
		ELSE V_RETURN := FIRST_VARCHAR; -- 如果不在范围内，则保留原字符
	  END CASE;
  END IF;

  RETURN V_RETURN;
END;

测试验证：

SQL> select fristPinyin('操作已执行') from dual;

行号     FRISTPINYIN('操作已执行')
---------- ------------------------------
1          C

SQL> select fristPinyin('a是正确的') from dual;

行号     FRISTPINYIN('a是正确的')
---------- ----------------------------
1          a

SQL> select fristPinyin('天天向上') from dual;

行号     FRISTPINYIN('天天向上')
---------- ---------------------------
1          T

SQL> select fristPinyin(' 不在') from dual;

行号     FRISTPINYIN('不在')
---------- ---------------------
1
已用时间: 1.805(毫秒). 执行号:667.
SQL> select fristPinyin('揄') from dual;

行号     FRISTPINYIN('揄')
---------- ------------------
1          Z