如何在excel中创建自定义函数来获取mysql数据？

We need to create a custom formula for users to pull data from our mysql database. After the user is authenticated, they would type in a formula in excel (something like '=retrievemybirthday("Frank Dodge")'. How do we go about doing that? We're not new to programming, just new to programming w/ Excel. Are there any tutorials on this? We've looked but can find anything. We need to create a custom formula for users to