How to solve unsuccessful SQL injection in sqlmap?

If the SQL injection is unsuccessful, it could be due to the following reasons:

1. The target website does not have any SQL injection vulnerabilities: injection attacks can only be successful on websites that have vulnerabilities. If after careful testing and analysis, it is confirmed that the target website does not have any SQL injection vulnerabilities, then injection attacks cannot be carried out.
2. Injecting point not correctly found: Before conducting an injection attack, it is essential to determine the location of the injection point. If the injection point is not correctly identified, the injection attack will not be successful. Injection points can be confirmed through the use of tools, manual injection, etc.
3. Incorrect injection statements: Injection statements are the key to injection attacks, and if the injection statement is incorrect, the injection attack cannot succeed. This can be addressed by adjusting the structure of the injection statement or trying different injection techniques.
4. The target website has implemented defense against injection attacks: some websites will defend against injection attacks by filtering, restricting special characters, etc. If the target website has defense mechanisms, the injection attack may not be successful. It is possible to try techniques to bypass the defense, or use other injection tools for the attack.
5. The server has undergone a security upgrade: some websites may fix and upgrade known vulnerabilities to enhance security. If the target website has been security upgraded, known injection vulnerabilities may have been fixed, making injection attacks unsuccessful. In this case, other types of vulnerability attacks can be attempted, or other vulnerability scanning tools can be used.

In summary, if SQL injection does not work, you can try the following methods: confirming if the target website has an SQL injection vulnerability, finding the correct injection point, adjusting the injection statement, bypassing defense mechanisms, or attempting other types of vulnerability attacks.