问将变量从函数中提取到其他函数中(在同一函数下)

EN

socket.on("db_rows", function() {
    setInterval(function() {
        
        var rows = 0;
        
        connection.query("SELECT COUNT(id) AS c FROM `systemusage`", function(error, result) {
            rows += result[0].c;
        });
        
        connection.query("SELECT COUNT(id) AS c FROM `temperature`", function(error, result) {
            rows += result[0].c;
        });
        
        connection.query("SELECT COUNT(id) AS c FROM `bmp280`", function(error, result) {
            rows += result[0].c;
        });
        
        console.log(rows);
        
        //var rows = (dbs.a + dbs.b + dbs.c);
        
        var value = (rows).toLocaleString(
            undefined,
            { minimumFractionDigits: 0 }
        );
            
        io.emit("db_rows", value);
    }, 2000)
});