CODEWITHSUNDEEP
phpsqloracle-databaseto-datesysdate
rji rji
rji rji

Reputation: 707

Not a valid month in oracle when add_months is used

I have given the below code in query.

    where to_date(cal_wid,'yyyymmdd') 
    between  add_months(to_date(sysdate, 'MM-YYYY'),-12) 
    and      to_date(sysdate, 'MM-YYYY')

I am getting the following bug. (I am doing in a Xampp server)

   Warning: oci_execute(): ORA-01843: not a valid month in C:\xampp\htdocs\xxx\index.php on line 149

   Warning: oci_fetch_array(): ORA-24374: define not done before fetch or execute and fetch in C:\xampp\htdocs\xxx\index.php on line 160

Can anyone tell why I am getting this error?

Upvotes: 2

Views: 6884

Answers (2)

Lalit Kumar B
Lalit Kumar B

Reputation: 49062

The error is here:

to_date(sysdate, 'MM-YYYY')

Let's see why:

SQL> select to_date(sysdate, 'MM-YYYY') from dual;
select to_date(sysdate, 'MM-YYYY') from dual
               *
ERROR at line 1:
ORA-01843: not a valid month


SQL>

You don't need to convert sysdate again into a date. Remove to_date and just use SYSDATE.

NOTE As an additional information, please look at @Boneist's answer for an insight regarding the implicit conversion that Oracle is forced to do while applying to_date on SYSDATE.

You use to_date to convert a string into a date. For date calculations, you just need to use the date value.

For example,

SQL> WITH DATA AS(
  2  SELECT '20150101' cal_wid FROM DUAL
  3  )
  4  SELECT *
  5  FROM DATA
  6  WHERE   to_date(cal_wid,'yyyymmdd')
  7  BETWEEN add_months(SYSDATE,-12)
  8  AND     SYSDATE
  9  /

CAL_WID
--------
20150101

SQL>

Modify your query as:

WHERE to_date(cal_wid,'yyyymmdd') BETWEEN add_months(SYSDATE, -12) AND SYSDATE

Upvotes: 1

Boneist
Boneist

Reputation: 23578

Never, ever use TO_DATE() on something that is already a DATE. The reason for this is because Oracle will have to do some implicit conversions in order to follow your wishes:

TO_DATE(sysdate, 'mm-yyyy')

is really run as

TO_DATE(TO_CHAR(sysdate, '<default nls_date_format parameter>'), 'mm-yyyy')

so if your nls_date_format is set to something that's other than 'mm-yyyy', you're going to have problems. The default nls_date_format parameter is 'DD-MON-YY', which is more than likely the value yours is set to.

If all you wanted to do was to add_months to the 1st of the current month, then you should use TRUNC(), eg:

add_months(trunc(sysdate, 'MM'),-12)

Here's proof of the implicit to_char if you to_date something that's already a date, as requested by Lalit - an execution plan of a basic query involving to_date(sysdate):

SQL_ID  3vs3gzyx2gtcn, child number 0
-------------------------------------
select *  from   dual where  to_date(sysdate) < sysdate

Plan hash value: 3752461848

----------------------------------------------------------------------------
| Id  | Operation          | Name | E-Rows |E-Bytes| Cost (%CPU)| E-Time   |
----------------------------------------------------------------------------
|   0 | SELECT STATEMENT   |      |        |       |     2 (100)|          |
|*  1 |  FILTER            |      |        |       |            |          |
|   2 |   TABLE ACCESS FULL| DUAL |      1 |     2 |     2   (0)| 00:00:01 |
----------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

   1 - filter(TO_DATE(TO_CHAR(SYSDATE@!))<SYSDATE@!)

You can clearly see the TO_CHAR() in the filter condition.

Upvotes: 5

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