Database cannot be applied. check whether the database exists and whether the user has the right to access the database.

The database is unavailable. check whether the database exists and whether the user has the right to access the php + mysql + Apache + zo configuration set up in the database locally, however, when the database information is installed and configured, [the database is unavailable. check whether the database exists and whether the user has the right to access the database.] What is the reason why the database is unavailable, check whether the database exists and whether the user has the right to access the database.
After the php + mysql + Apache + zo configuration is set up locally, everything works normally. However, when the database information is installed and configured, the following error occurs: [unavailable database, check whether the database exists and whether the user has the right to access the database. what is the reason?

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Where did you see the prompt? Mysql has no data on the root account ......