Function perfomed by SQL query-CodePudding

I am a new learner to SQL,and I couldn't understand what the following queries do:

Select to_char(sal ,’$99,999’) salary from emp where ename =’SCOTT’ ;
Select to_date(’07-july-03’,’RM’) from dual ;

Please help.

CodePudding user response：

The best option you could have done would be to actually execute those queries and see what they return.

1st query: to_char formats number (salary is a number) so that it is displayed in desired format. In your case, it adds dollar sign in front of it as well as the thousands separator.

SQL> select sal original_value,
  2        to_char(sal, '$99,999') formatted_value
  3  from emp
  4  where ename = 'SCOTT';

ORIGINAL_VALUE FORMATTE
-------------- --------
          3000   $3,000

2nd query: RM format model returns Roman month (today is April, it is the 4th month in a year, its Roman representation is IV).

SQL> select sysdate,
  2         to_char(sysdate, 'dd.mm.yyyy') formatted,
  3         to_char(sysdate, 'RM') roman
  4  from dual;

SYSDATE   FORMATTED  ROMA
--------- ---------- ----
03-APR-22 03.04.2022 IV

SQL>

Your 2nd query, on the other hand, seems to be invalid:

SQL> select to_date('03-apr-22', 'RM') your_query from dual;
select to_date('03-apr-22', 'RM') your_query from dual
               *
ERROR at line 1:
ORA-00012: Message 12 not found;  product=RDBMS; facility=ORA
; arguments: [12]


SQL>

More about format models in documentation.