Oracle's conversion functions

Convert a date to character

1. Grammar

 

 

Default format DD-MON-RR

YY YYYY YEAR (English year)

MM MONTH (English Month)

DD DAY

HH24 HH12

MI SS

2. Examples

1. SQL>select to_char(sysdate,'YYYY-MM-DD HH24:MI:SS')from dual;
3. TO_CHAR(SYSDATE,'YY
4. -------------------
5. 2017-07-02 11:40:14
7. SQL> select to_char(sysdate,'YYYY-MM-DD HH12:MI:SS') from dual;
9. TO_CHAR(SYSDATE,'YY
10. -------------------
11. 2017-07-0211:40:38

 

Convert two characters to date

1. Grammar

TO_DATE(char[,fmt[,params]])

params: the language used to make the date

Note: to_date() displays in the system default date format

2. Examples

1. SQL>select to_date('2017-7-2','YYYY-MM-DD')from dual;
3. TO_DATE('2017-
4. --------------
5. 02-7月 -17

 

Convert three numbers to characters

1. Grammar

TO_CHAR(number[,fmt])

9: Display the number and ignore the leading 0

0: Display the number, if the number of digits is insufficient, fill it with 0

.or D: Display decimal point

, or G: display thousands

$: dollar sign

S: plus plus or minus sign (both before and after)

2. Examples

1. SQL>select to_date('2017-7-2','YYYY-MM-DD')from dual;
3. TO_DATE('2017-
4. --------------
5. 02-7月 -17
7. SQL> select to_char(12345.678,'$99,999.999') from dual;
9. TO_CHAR(1234
10. ------------
11. $12,345.678
13. SQL> select to_char(12345.678,'$99,999,999') from dual;
15. TO_CHAR(1234
16. ------------
17. $12,346
19. SQL> select to_char(12345.678,'S99,999.999') from dual;
21. TO_CHAR(123
22. -----------
23. +12,345.678

 

Convert four characters to numbers

1. Grammar

TO_NUMBER(char[,fmt])

fmt is the converted format and can be omitted

2. Examples

1. SQL>select to_number('$1,000','$9999')from dual;
3. TO_NUMBER('$1,000','$9999')
4. ---------------------------
5. 1000