Fix Oracle EXTRACT Function Issues

If data cannot be retrieved using the EXTRACT function in Oracle, follow these steps to troubleshoot and resolve the issue.

1. Make sure the table being queried contains the data to be extracted. You can use a SELECT statement to check if the table contains the data.
2. Ensure that the specified criteria for the query are correct. The EXTRACT function requires specifying the part to be extracted (such as the year or month) as well as the date field to be extracted from. Make sure that the part to be extracted and the date field match correctly.
3. Ensure that the date field is formatted correctly. When using the EXTRACT function, the correct date format needs to be provided. You can use the TO_CHAR function to convert the date field to the specified format before extracting with the EXTRACT function.
4. Ensure that the extracted field names are correct. When using the EXTRACT function, make sure to specify the field name after extraction. Ensure that the specified field name matches the field names in the query results.
5. If the above steps do not solve the problem, you can try using other date functions such as TO_CHAR, TO_DATE, TRUNC, etc., to obtain specific parts of the date.

If the issue remains unresolved, it may be necessary to further examine the database table structure, data integrity, and the correctness of the query statements. Additionally, consulting the error logs of the Oracle database or seeking assistance from a database administrator or developer could also be considered for further help.