IMHO: Don't take on learning everything at once. For instance, if you want to make a mobile app that hits a php web service with a mysql db, start with web service and its language. You can dummy data inputs that would normally come from the mobile app via CLI or GET/POSTs and instead of writing to a DB, just echo what you would be writing to a log somewhere.
To me, anyway, it's like a foreign language. If you try to learn 3 in tandem, you may end up slowing yourself down. Get to a reasonable degree of fluency in one and the others will be easier.
Also, I don't recommend having a mobile app interface with your database directly. Always expose a web service and have it interface with your db. The great part about this work is that it sets you up for exposing a public API in the future, should you decide.
To me, anyway, it's like a foreign language. If you try to learn 3 in tandem, you may end up slowing yourself down. Get to a reasonable degree of fluency in one and the others will be easier.
Also, I don't recommend having a mobile app interface with your database directly. Always expose a web service and have it interface with your db. The great part about this work is that it sets you up for exposing a public API in the future, should you decide.