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This article will explain in detail how to deal with database selection failure in php. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

The solution to the failure of database selection in php: 1. Check mysql_select_db and mysqli_select_db;2 and modify the order of the incoming parameters of the two connection methods.

This article operating environment: Windows7 system, PHP7.1 version, Dell G3 computer.

PHP connection to the database appears "failed to select database"?

When PHP connects to the database:

It's okay to connect to the database with mysqli_connect, but it's always wrong when mysqli_select_db! I'm puzzled.

After careful observation of mysql_select_db and mysqli_select_db, it was found that

The parameter passed in to mysql_select_db is ($databaseName,$query)

The parameter passed in to mysqli_select_db is ($query,$databaseName)

At this point, the order of the input parameters of the original two connection methods is not the same, so the choice will fail.

This is the end of this article on "how to deal with database selection failure in php". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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