Oracle数据的字符串操作

常用的SQL语句中的字符串操作函数

--not in 操作
-- SELECT T.LAST_NAME, T.JOB_ID FROM EMPLOYEES T WHERE JOB_ID NOT IN ('IT_PROG','SA_MAN')

--UPPER大写、Lower小写操作、首字母大写INITCAP
--SELECT  LAST_NAME , UPPER(LAST_NAME), LOWER(LAST_NAME) , INITCAP(LAST_NAME) FROM EMPLOYEES
--SELECT LAST_NAME, SALARY, JOB_ID FROM EMPLOYEES WHERE JOB_ID IN  ('IT_PROG', 'SA_MAN')
--SELECT LAST_NAME, SALARY, JOB_ID FROM EMPLOYEES WHERE UPPER( JOB_ID) IN ('IT_PROG', 'SA_MAN')

 --连接符||操作
--SELECT LAST_NAME||'   ' ||FIRST_NAME FROMEMPLOYEES;
--SELECT  LAST_NAME, FIRST_NAME,CONCAT(LAST_NAME,FIRST_NAME) FROM EMPLOYEES
--SELECT  LAST_NAME,FIRST_NAME,CONCAT(CONCAT(LAST_NAME, '_') , FIRST_NAME)FROM EMPLOYEES

--SUBSTR操作
--SELECT  SUBSTR('HelloWorld', 1, 5) FROM DUAL;
--SELECT SUBSTR('HelloWorld', 2, 6) FROM DUAL;
--SELECT SUBSTR('HelloWorld', 8) FROM DUAL;
--SELECT CONCAT(LAST_NAME, FIRST_NAME), SUBSTR(CONCAT(LAST_NAME , FIRST_NAME), 2, 5)FROM EMPLOYEES
--SELECT CONCAT(LAST_NAME, FIRST_NAME), SUBSTR(LAST_NAME||FIRST_NAME, 2, 5) FROMEMPLOYEES

--LENGTH操作
--SELECT LENGTH('HelloWorld') FROM DUAL;
--SELECT  LAST_NAME,LENGTH(LAST_NAME), CONCAT(LAST_NAME, FIRST_NAME), LENGTH(CONCAT(LAST_NAME ,FIRST_NAME)) FROM EMPLOYEES
--INSTR
--SELECT INSTR('HelloWorld', 'l',2,2) FROM DUAL;
--SELECT INSTR('HelloWorld', 'l') FROM DUAL;
--SELECT INSTR('HelloWorld', 'l',5) FROM DUAL

--TRIM操作
--SELECT TRIM('b'FROM 'ballab') FROM DUAL;
--SELECT TRIM('b'FROM 'ba123ba') FROM DUAL;
--SELECT TRIM(BOTH'b' FROM 'ballab') FROM DUAL;
--SELECTTRIM(LEADING 'b' FROM 'ballab') FROM DUAL;
--SELECT TRIM(TRAILING 'b' FROM 'ballab') FROM DUAL;
--SELECT TRIM('b'FROM TRIM('a' FROM TRIM('b' FROM 'ballba')))FROM DUAL
--SELECT TRIM('b'FROM TRIM('a' FROM TRIM('b' FROM 'ab123ab'))) FROM DUAL
--LTRIM和RTRIM
--SELECT LTRIM('ab123ab', 'ab') FROM DUAL;
--SELECT RTRIM('ab123ab', 'ab') FROM DUAL;
--SELECT LTRIM(RTRIM('ab123ab', 'ab'), 'ab') FROM DUAL;