You can't communicate directly with SQL from Angular. You are going to need a server side language to act as a middle man. The choice of which language really depends on what you have experience with. Assuming you are referring to Microsoft's SQL Server, a language like C# offers first class support but I fear the learning curve would be too high if you don't already have experience with it. Since you do know JavaScript, you can try something like NodeJS for your backend and use an npm package like tedious to connect.
Does it have to be SQL? You can try something like firebase which is a "backend as a service" meaning you can create your angular apps and write/retrieve information from a database securely. Whats more, one connects directly to it without needing to deal with writing up a bespoke API. There's even a angular module for it. I would recommend going this route if you are uncomfortable with the first approach.