Oracle中INSTR和SUBSTR的用法
Oracle中INSTR的用法: INSTR方法的格式為INSTR(源字串, 要查詢的字串, 從第幾個字元開始, 要找到第幾個匹配的序號)返回找到的位置,如果找不到則返回0.例如:INSTR('CORPORATE FLOOR','OR', 3, 2)中,源字串為'CORPORATE FLOOR', 在字串中查詢'OR',從第三個字元位置開始查詢"OR",取第三個字後第2個匹配項的位置。
預設查詢順序為從左到右。當起始位置為負數的時候,從右邊開始查詢。
所以SELECT INSTR('CORPORATE FLOOR', 'OR', -1, 1) "aaa" FROM DUAL的顯示結果是
Instring——————14
oracle的substr函式的用法: 取得字串中指定起始位置和長度的字串 substr( string, start_position, [ length ] ) 如: substr('This is a test', 6, 2) would return 'is' substr('This is a test', 6) would return 'is a test' substr('TechOnTheNet', -3, 3) would return 'Net' substr('TechOnTheNet', -6, 3) would return 'The' select substr('Thisisatest', -4, 2) value from dual
綜合應用:SELECT INSTR('CORPORATE FLOOR', 'OR', -1, 1) "Instring" FROM DUAL--INSTR(源字串, 目標字串, 起始位置, 匹配序號)SELECT INSTR('CORPORATE FLOOR','OR', 3, 2) "Instring" FROM DUAL
SELECT INSTR('32.8,63.5',',', 1, 1) "Instring" FROM DUAL
SELECT SUBSTR('32.8,63.5',INSTR('32.8,63.5',',', 1, 1)+1) "INSTRING" FROM DUALSELECT SUBSTR('32.8,63.5',1,INSTR('32.8,63.5',',', 1, 1)-1) "INSTRING" FROM DUAL
-- CREATED ON 2008-9-26 BY ADMINISTRATOR DECLARE -- LOCAL VARIABLES HERE T VARCHAR2(2000); S VARCHAR2(2000); NUM INTEGER; I INTEGER; POS INTEGER;BEGIN -- TEST STATEMENTS HERE T := '12.3,23.0;45.6,54.2;32.8,63.5;'; SELECT LENGTH(T) - LENGTH(REPLACE(T, ';', '')) INTO NUM FROM DUAL; DBMS_OUTPUT.PUT_LINE('NUM:' || NUM); POS := 0; FOR I IN 1 .. NUM LOOP DBMS_OUTPUT.PUT_LINE('I:' || I); DBMS_OUTPUT.PUT_LINE('POS:' || POS); DBMS_OUTPUT.PUT_LINE('==:' || INSTR(T, ';', 1, I)); DBMS_OUTPUT.PUT_LINE('INSTR:' || SUBSTR(T, POS + 1, INSTR(T, ';', 1, I) - 1)); POS := INSTR(T, ';', 1, I); END LOOP;END;
-- Created on 2008-9-26 by ADMINISTRATOR declare -- Local variables here i integer; T VARCHAR2(2000); S VARCHAR2(2000);begin -- Test statements here --歷史狀態 T := '12.3,23.0;45.6,54.2;32.8,63.5;'; IF (T IS NOT NULL) AND (LENGTH(T) > 0) THEN --T := T || ','; WHILE LENGTH(T) > 0 LOOP --ISTATUSID := 0; S := TRIM(SUBSTR(T, 1, INSTR(T, ';') - 1)); IF LENGTH(S) > 0 THEN DBMS_OUTPUT.PUT_LINE('LAT:'||SUBSTR('32.8,63.5',1,INSTR('32.8,63.5',',', 1, 1)-1)); DBMS_OUTPUT.PUT_LINE('LON:'||SUBSTR('32.8,63.5',INSTR('32.8,63.5',',', 1, 1)+1));/* INSERT INTO T_HISTORY_RESPONSESTATUS (HISTORYID, RESPONSESTATUSID, STAMP, CALL_LETTER) VALUES (IHISTORYID, S, ISTAMP, ICALL_LETTER);*/ -- COMMIT; END IF; T := SUBSTR(T, INSTR(T, ';') + 1); END LOOP; END IF; end;