Oracle 适用函数：获取字符串的第一个拼音字母

create or replace function FN_GETSPELLCODING
(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..LENGTH(P_NAME) 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';
 END IF;
 END LOOP;
 RETURN V_RETURN;
 END;

 select FN_GETSPELLCODING('爱') from dual