取汉字拼音头字母的实现

运行下面的PL/SQL生成函数
CREATE OR REPLACE FUNCTION to_piny(P_NAME IN VARCHAR2) RETURN VARCHAR2 AS
V_COMPARE VARCHAR2(100);
V_RETURN VARCHAR2(4000);
FUNCTION F_NLSSORT(P_WORD IN VARCHAR2) RETURN VARCHAR2 AS
BEGIN
RETURN NLSSORT(P_WORD, 'NLS_SORT=SCHINESE_PINYIN_M');
END;
BEGIN
FOR I IN 1..NVL(LENGTH(P_NAME), 0) LOOP
 V_COMPARE := F_NLSSORT(SUBSTR(P_NAME, I, 1));
IF V_COMPARE >= F_NLSSORT('吖') AND V_COMPARE <= F_NLSSORT('驁') THEN
V_RETURN := V_RETURN || 'A';
ELSIF V_COMPARE >= F_NLSSORT('八') AND V_COMPARE <= F_NLSSORT('簿') THEN
 V_RETURN := V_RETURN || 'B';
ELSIF V_COMPARE >= F_NLSSORT('嚓') AND V_COMPARE <= F_NLSSORT('錯') THEN
 V_RETURN := V_RETURN || 'C';
ELSIF V_COMPARE >= F_NLSSORT('咑') AND V_COMPARE <= F_NLSSORT('鵽') THEN
V_RETURN := V_RETURN || 'D';
 ELSIF V_COMPARE >= F_NLSSORT('妸') AND V_COMPARE <= F_NLSSORT('樲') THEN
V_RETURN := V_RETURN || 'E';
ELSIF V_COMPARE >= F_NLSSORT('发') AND V_COMPARE <= F_NLSSORT('猤') THEN
V_RETURN := V_RETURN || 'F';
ELSIF V_COMPARE >= F_NLSSORT('旮') AND V_COMPARE <= F_NLSSORT('腂') THEN
 V_RETURN := V_RETURN || 'G';
ELSIF V_COMPARE >= F_NLSSORT('妎') AND V_COMPARE <= F_NLSSORT('夻') THEN
V_RETURN := V_RETURN || 'H';
 ELSIF V_COMPARE >= F_NLSSORT('丌') AND V_COMPARE <= F_NLSSORT('攈') THEN
V_RETURN := V_RETURN || 'J';
ELSIF V_COMPARE >= F_NLSSORT('咔') AND V_COMPARE <= F_NLSSORT('穒') THEN
 V_RETURN := V_RETURN || 'K';
 ELSIF V_COMPARE >= F_NLSSORT('垃') AND V_COMPARE <= F_NLSSORT('擽') THEN
 V_RETURN := V_RETURN || 'L';
 ELSIF V_COMPARE >= F_NLSSORT('嘸') AND V_COMPARE <= F_NLSSORT('椧') THEN
 V_RETURN := V_RETURN || 'M';
ELSIF V_COMPARE >= F_NLSSORT('拏') AND V_COMPARE <= F_NLSSORT('瘧') THEN
 V_RETURN := V_RETURN || 'N';
 ELSIF V_COMPARE >= F_NLSSORT('筽') AND V_COMPARE <= F_NLSSORT('漚') THEN
V_RETURN := V_RETURN || 'O';
 ELSIF V_COMPARE >= F_NLSSORT('妑') AND V_COMPARE <= F_NLSSORT('曝') THEN
V_RETURN := V_RETURN || 'P';
 ELSIF V_COMPARE >= F_NLSSORT('七') AND V_COMPARE <= F_NLSSORT('裠') THEN
 V_RETURN := V_RETURN || 'Q';
ELSIF V_COMPARE >= F_NLSSORT('亽') AND V_COMPARE <= F_NLSSORT('鶸') THEN
V_RETURN := V_RETURN || 'R';
 ELSIF V_COMPARE >= F_NLSSORT('仨') AND V_COMPARE <= F_NLSSORT('蜶') THEN
 V_RETURN := V_RETURN || 'S';
 ELSIF V_COMPARE >= F_NLSSORT('侤') AND V_COMPARE <= F_NLSSORT('籜') THEN
 V_RETURN := V_RETURN || 'T';
 ELSIF V_COMPARE >= F_NLSSORT('屲') AND V_COMPARE <= F_NLSSORT('鶩') THEN
 V_RETURN := V_RETURN || 'W';
ELSIF V_COMPARE >= F_NLSSORT('夕') AND V_COMPARE <= F_NLSSORT('鑂') THEN
 V_RETURN := V_RETURN || 'X';
ELSIF V_COMPARE >= F_NLSSORT('丫') AND V_COMPARE <= F_NLSSORT('韻') THEN
 V_RETURN := V_RETURN || 'Y';
 ELSIF V_COMPARE >= F_NLSSORT('帀') AND V_COMPARE <= F_NLSSORT('咗') THEN
V_RETURN := V_RETURN || 'Z';
ELSIF V_COMPARE = F_NLSSORT('1') THEN
 V_RETURN := V_RETURN || 'Y';
ELSIF V_COMPARE = F_NLSSORT('2') THEN
 V_RETURN := V_RETURN || 'R';
ELSIF V_COMPARE = F_NLSSORT('3') THEN
 V_RETURN := V_RETURN || 'S';
ELSIF V_COMPARE = F_NLSSORT('4') THEN
 V_RETURN := V_RETURN || 'S';
ELSIF V_COMPARE = F_NLSSORT('5') THEN
 V_RETURN := V_RETURN || 'W';
ELSIF V_COMPARE = F_NLSSORT('6') THEN
 V_RETURN := V_RETURN || 'L';
ELSIF V_COMPARE = F_NLSSORT('7') THEN
 V_RETURN := V_RETURN || 'Q';
ELSIF V_COMPARE = F_NLSSORT('8') THEN
 V_RETURN := V_RETURN || 'B';
ELSIF V_COMPARE = F_NLSSORT('9') THEN
 V_RETURN := V_RETURN || 'J';
ELSIF V_COMPARE = F_NLSSORT('0') THEN
 V_RETURN := V_RETURN || 'L';
 END IF;
END LOOP;
RETURN V_RETURN;
 END;
/
 
通过以下方法调用
 
SQL> SELECT to_piny('5') FROM DUAL;
TO_PINY('5')
--------------------------------------------------------------------------------
W
 
SQL> SELECT to_piny('天下') FROM DUAL;
TO_PINY('天下')
--------------------------------------------------------------------------------
TX