Invalid Oracle ORA-00904 identifier __oracle

ORA-00904 Invalid identifier
The reason for this error is most likely that one of the field names in your SQL statement is incorrectly written,

or the table name is wrong, and so on, in short, it is very complicated! The field name does not correspond to the table, it may have this table, but the field is not, or the table does not exist.

For example: Select Deptname from stu;//at this point, Stu table does not have deptname this field

Or

Select Deptname from abcd;//at this time ABCD this table is a table that does not exist in a database, in other words, you are writing the wrong table name.

All these, such as INSERT INTO dept (Deptno,deptname,stuno) VALUES (...) will also appear the same error, because there is no Stuno field in Dept.

It's also possible that when you create a table, the last field is created with a comma.