如何将mysql值存储到变量中？

Question

我想将我的mysql查询中的检索值存储到一个变量中，以便我可以将该值插入到另一个表中。

下面是检索值

connectionSelectPackageId.connect(); 

    let sqlSelectPackageId = "SELECT MAX(packageId) as maxId FROM recipients"; 

    connectionSelectPackageId.query(sqlSelectPackageId, function(err, rows){ 
    if(err) { 
    throw err; 
    } else { 

     for(var i=0; i< rows.length; i++) { 

      console.log(rows[i].maxId); 
    }; 
    }; 
}); 


    connectionSelectPackageId.end(); 

我知道我是正确的检索值，因为当我安慰出来它打印出正确的数量

 console.log(rows[i].maxId); 

我想查询存储值工作通过连接结束（connectionSelectPackageId.end();）

在此先感谢

connectionInsert.connect（）;

// Insert into the recipients the hashtag and information needed to opon the lock 

function getDateTime() { 
    var now  = new Date(); 
    var year = now.getFullYear(); 
    var month = now.getMonth()+1; 
    var day  = now.getDate(); 
    var hour = now.getHours(); 
    var minute = now.getMinutes(); 
    var second = now.getSeconds(); 
    if(month.toString().length == 1) { 
     var month = '0'+month; 
    } 
    if(day.toString().length == 1) { 
     var day = '0'+day; 
    } 
    if(hour.toString().length == 1) { 
     var hour = '0'+hour; 
    } 
    if(minute.toString().length == 1) { 
     var minute = '0'+minute; 
    } 
    if(second.toString().length == 1) { 
     var second = '0'+second; 
    } 
    var dateTime = year+'/'+month+'/'+day+' '+hour+':'+minute+':'+second; 
    return dateTime; 
} 

var dateTime = getDateTime(); 

    // Add email later on 
    let sqlInsert = 'INSERT INTO recipients (date, ..., ..., ..., ..., ..., ..., data) VALUES (?, ?, ?, ?, ?, ?, ?, ?)'; 

    connectionInsert.query(sqlInsert, [dateTime, ..., ..., ...,...,..., ..., data], function(err, rows, fields) { 
    }); 

connectionInsert.end(); 

的数据是在第一查询或rows[i].maxId

Answer 1

使用无极或回调函数抓起值。

这是你想要的东西吗？

connectionSelectPackageId.connect(); 

var getSomeValues = function getSomeValues() { 
    return new Promise(function (resolve, reject) { 
     let sqlSelectPackageId = "SELECT MAX(packageId) as maxId FROM recipients"; 
     connectionSelectPackageId.query(sqlSelectPackageId, function (err, rows) { 
      if (err) { 
       return reject(err); 
      } else { 
       return resolve(rows); 
      }; 
     }); 
    }); 
} 

getSomeValues().then(function(rows) { 
    // do something with rows here 

}).catch(function (err) { 
    console.log(err); 
}); 

connectionSelectPackageId.end();