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ORA-00904: STRING: invalid identifier tips

Oracle Error Tips by Burleson Consulting


Question:  I am running a SQL statement and I get a SQL*Plus error ORA-00904 invalid identifier.


Answer: When ORA-00904 occurs, you must enter a valid column name as it is either missing or the one entered is invalid. The "invalid identifier" most common happens when you are referencing an invalid alias in a select statement.  The Oracle docs note this on the ORA-00904 error:


ORA-00904 string: invalid identifier

Cause: The column name entered is either missing or invalid.
Action: Enter a valid column name. A valid column name must begin with a letter, be less than or equal to 30 characters, and consist of only alphanumeric characters and the special characters $, _, and #.

If it contains other characters, then it must be enclosed in double quotation marks. It may not be a reserved word.

To avoid ORA-00904, column names cannot be a reserved word, and must contain these four criteria to be valid:

  • begin with a letter
  • be less than or equal to thirty characters
  • consist only of alphanumeric and the special characters ($_#); other characters need double quotation marks around them

Another important factor in correcting ORA-00904 is remembering to run catproc.sql

You can also check your trace file to find the particular error which is causing the ORA-00904 to occur. 

You can find case for review regarding error ORA-00904 at this congruent Burleson Consulting site.




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