ORA-01722 invalid number

Cause: The attempted conversion of a character string to a number failed because the character string was not a valid numeric literal. Only numeric fields or character fields containing numeric data may be used in arithmetic functions or expressions. Only numeric fields may be added to or subtracted from dates.

Action: Check the character strings in the function or expression. Check that they contain only numbers, a sign, a decimal point, and the character "E" or "e" and retry the operation.

The following sql successfully creates the  error, we are comparing  a number to a character.

 

SQL> SELECT 'X'
  2  FROM DUAL
  3  WHERE 1='A';
WHERE 1='A'
        *
ERROR at line 3:
ORA-01722: invalid number

 

But it can get more interesting as seen below. A number is inserted into a varchar2 column. In the following sql’s , when we select the varchar2 column first  and the number column next , the sql does not fail. But if we do the other way round the sql fails as the where clause checks for 999 in all the values for the varchar2 column. When it tries to compare 999 to ‘STRING’ it fails.

 

This particular pattern can cause the invalid number error especially when creating queryies dynamically, or when we run reports depending on the parameters entered for a given report.

SQL> desc test
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 LV_NUMBER                                          NUMBER
 LV_VARCHAR2                                        VARCHAR2(10)

SQL> select * from test;

 LV_NUMBER LV_VARCHAR
---------- ----------
         1 STRING
         2 999

  1  select t.*
  2   from  test t
  3  where lv_number=2 and
  4*       lv_varchar2=999
SQL> /
      lv_varchar2=999
      *
ERROR at line 4:
ORA-01722: invalid number

  1  select t.*
  2   from  test t
  3  where lv_varchar2=999 and
  4*       lv_number=2
  5  /

 LV_NUMBER LV_VARCHAR

---------- ----------

         2 999