ORA-00904 invalid identifier has used an invalid identifier or an incorrect and unqualified syntax in your statement. The error occurred in SELECT or INSERT queries in SQL and UPDATE, DELETE, CREATE TABLE and ALTER TABLE. Most errors occur only by case-sensitive problems, but some users won’t believe this. Generally, oracle treats identifiers as case insensitive ones except for the password. It alerts users for invalid table names. There are two legal ways to name an object that are non-quoted identifiers and quoted identifiers.
Non-quoted identifiers
Punctuation marks or special treatments do not surround it. It can be used case-insensitively and flexibly in SQL and is also regarded as upper-cased ones.
Quoted identifiers
It begins and ends with double quotation marks (“); using these quotation marks, you can put every character and white spaces. These identifiers must be used as is originally defined and followed.
How to solve the ORA-00904 error message?
Suppose you are facing an error message while using SQL. In that case, that might be if statements include an invalid column name and statements include an invalid column name that does not currently exist. First, you should check whether the column name exists or not. If the column name exists, check that the column name is in proper syntax. If you want to understand any error, you must know how to reproduce it. Until you know the cause, you won’t understand the real meaning of that error. Here are some tips for column names that should be valid.
- The column name should not be a reserved word.
- The column name’s first letter must be a letter, and it must be less than or equal to 30 characters.
- The column name should be alphanumeric characters, and it must contain any one of these $, _, #
- If the column name includes any other characters, it should be enclosed with (“).
- When referring to the column, you must check if your column name exists or not.
