What is the difference between openid and appid?
For the same user, the AppID used by a platform will generate a corresponding OpenID for him. If these platform applications are all bound under the same WeChat open platform, then these OpenIDs of this user will all correspond to the same UnionID
What is openid?
open id: After the follower interacts with the official account, the official account can obtain the open id of the follower. For the same user, there are different open ids corresponding to different official accounts or mobile applications to identify each application and each user under each application. Each has a unique openid, which is used to identify the identity of this user under this application (the only type in the user table Primary Key)
What is a unionid?
union id: the same user has the same unionID under different official accounts or mobile applications; the premise is that if multiple official accounts and mobile application accounts need to be interoperable to obtain a unique identity union id, multiple official accounts or mobile applications need to be linked together. The application is bound on the WeChat open platform, and then we can get the union id
Under the same subject, different applications identify the unique identity between them is unionid
