If you ever worked with Oracle Database, then you would definitely come across ORA-00904: invalid identifier error, irrespective of the matter with the version on which you are working like 10g, 11g, or 12g, and is most prominent error comes while doing CRUD (create, read, update and delete) operation in Oracle. What should be done on getting this error during SQL script? Invalid identifier means that column name entered is either missing or invalid, since this not the only error that occurs with SQL script but is one of the most common. This article is all about the solution in order to get rid of this error. Cause of error: Below are few causes that lead to error ORA-00904 or Invalid Identifier; Reason 1: Due to extra comma at last column An extra comma at the end of create table statement can lead to “ORA-00904 or “invalid identifier”, and is by far noticed as a most common reason. It creeps in as a result of copy and paste culture, because mostly users while copying do not pay attention in between commas and Oracle expects another column declaration after comma. So it’s better to explicitly check the last column declaration rather than finding it while running query against database. Reason 2: Due to incorrect column name in DELETE query Similarly to previous example of SELECT and UPDATE query, you will also face “ORA-00904: invalid identifier” if you give wrong column name in DELETE statements. It could be due to typo of recent update in schema which dropped the column you are using in your DELETE clause. Reason 3: Invalid identifier While Inserting data into Table Apart from table creation, you will see error “ORA-00904: invalid identifier” if you use wrong column name in INSERT statement or use a non-existent column name. Most of the time it happens because of typo, but some other time it could be due to parallel update e.g. someone changed the schema of table and renamed or dropped the column you are referring in INSERT query. If still you are not able to Oracle Database even after following above steps, then you can opt for a recovery tool that is Oracle File Repair tool. This tool can help you to recover all files and objects from Oracle database. It not only supports Oracle 11G version but is also compatible with other version of Oracle. It scans the database deeply and if there is any error or corruption it fixes them and restores the data.