In this example, a SELECT statement is missing an expression after the WHERE clause:
SQL> SELECT * FROM employees WHERE; SELECT * FROM employees WHERE * ERROR at line 1: ORA-00936: missing expression
This query will result in ORA-00936 because the WHERE clause requires a condition to be specified.
Incorrect use of Oracle reserved words can also trigger ORA-00936:
SQL> SELECT FROM employees; SELECT FROM employees * ERROR at line 1: ORA-00936: missing expression
In this case, the SELECT statement is missing the list of columns to select from the employees table, resulting in ORA-00936.