How to query whether database exists in php

How to query whether the database exists: first create a new instance of MySQL or MySQL; then execute the statement "SELECT COUNT(*) AS `exists` FROM..."; finally check the value of the key exists, and Just check whether the database exists.

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Create a new instance of MySQL or MySQL (without specifying a default database) , and execute the following query (similar to Marc B's comment):

SELECT COUNT(*) AS `exists` FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMATA.SCHEMA_NAME='my_database_name'

Then you can check the value of key exists to see if the database exists.

The following is a sample code:

// statement to execute
$sql = 'SELECT COUNT(*) AS `exists` FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMATA.SCHEMA_NAME="my_database_name"';
// execute the statement
$query = $mysqli->query($sql);
if ($query === false) {
    throw new Exception($mysqli->error, $mysqli->errno);
}
// extract the value
$row = $query->fetch_object();
$dbExists = (bool) $row->exists;

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