我们希望函数返回一个承诺并关闭数据库连接。最后，我们在try和connection closing命令中加入了promise，它给出了以下错误-

conPool.close()  //It says  Error - conPool.close() is not a function

conPool.release() // Error - conPool.release() is not a function

conPool.releaseConnection(); // Error - Cannot read property '_pool' 
                                          of undefined

请帮我关闭mysql连接。我想归还我的数据。但在返回后，没有任何工作，因此连接不会关闭。恐怕我可能会超出最大限度。我甚至在mysql中设置了最大连接数，但仍然是。有一个可能的解决方案，我可以在函数外部声明conpool，让所有函数都使用这个conpool，但这也不起作用。
代码-

function viewChoice() {

    var sqlQuery;

        sqlQuery = "select * from TRANSACTION_PAYLOAD where INTERFACE_NAME 
     = 'Vehicle RC' AND (STATUS ='INPUT_ERROR' OR STATUS ='ERROR')";

    }

    var deferred = Q.defer();

    var host = config.host;
    var user = config.user;
    var password = config.password;
    var database = config.database;

    var conPool = mysql.createPool({
        host: host,
        user: user,
        password: password,
        database: database
    });

try{
    conPool.getConnection(function (err) {
        console.log("Inside getConnection ")
        if (err)
            deferred.reject(err.name + ': ' + err.message);

        conPool.query(sqlQuery,
            function (err, result, fields) {
                if (err) deferred.reject(err.name + ': ' + err.message);

                console.log(result);
                deferred.resolve(result);
            });
    });
    return deferred.promise;
}

finally{
    console.log("inside  Finally")
    conPool.releaseConnection();

}

}