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
综合应用:
SELECT INSTR('CORPORATE FLOOR', 'OR', -1, 1) "Instring" FROM DUAL
--INSTR(源字符串, 目标字符串, 起始位置, 匹配序号)
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 DUAL
SELECT 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
--历史状态
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));
-- COMMIT;
END IF;
T := SUBSTR(T, INSTR(T, ';') + 1);
END LOOP;
END IF;
end;
SELECT SUBSTR('This is a test', 0, 2) value from dual; 返回值Th
SELECT SUBSTR('This is a test', 1, 2) value from dual; 返回值Hi
SELECT SUBSTR('This is a test', -1, 2) value from dual; 返回值t
SELECT SUBSTR('This is a test', -2, 2) value from dual; 返回值st