Add SQL docs

[root-0101]

As database is an important part of IT so, adding the SQL docs will be beneficial

[github-actions]

Hi @root-0101! Thanks for opening this issue. We appreciate your contribution to this open-source project. Your input is valuable and we aim to respond or assign your issue as soon as possible. Thanks again!

[github-actions]

Hello @root-0101! Your issue #2899 has been closed. Thank you for your contribution!