[Oracle database] mammy tutorial day14 conversion function

Conversion function

1、ASCII(str) Convert a character into a ASCII code

SELECT ASCII('a') FROM DUAL;

2、CHR(num) according to ascii Convert to corresponding 97 character

SELECT CHR(97) FROM dual;

3、to_number(str) Convert a character type number to a numeric type number

SELECT to_number('123') FROM dual;

4、to_date(str,' Format ') Put the string Convert to date

SELECT DATE '1999-09-09',
       TO_DATE('1999-09-09','YYYY-MM-DD') 
 FROM DUAL;

5、to_char( date , Format ) Convert date to character format

SELECT TO_char(SYSDATE,'yyyy') FROM dual;

6、to_char(NUM,' Format ')

Self rounding
9 Place holder
0 Place holder （ bits ）
$ Dollar symbol
L Local currency

SELECT TO_CHAR(33.14,'L99.999') FROM DUAL;