ORA-00904 error messages

Symptom: using a query statement in a table results in a field that does not recognize the error ORA-00904: "callid": Invalid identifier, but this field exists when displaying with DESC, then, replace the query statement with double quotation marks and execute the statement.

Official explanation of the 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.

 

Actual cause: the Case sensitivity settings are set in the database.