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node.js - nodejs查询数据库执行顺序不太对。。怎么同步查询

会展小控发布于 2022-11-02 12:08

直接上代码

var resu;
var db = require("./dbs.js?1.2.1");
var http=require("http");
var server=http.createServer(function(req,res){
    if(req.url!=="/favicon.ico"){
        resu = db.searchDb();
        res.writeHead(200,{"Content-Type":"text/plain","Access-Control-Allow-Origin":"*"});
        res.write(resu);
    }
    res.end();
});
server.listen(1338,"localhost",function(){
    console.log("开始监听...");
});

这个是数据库查询的文件

exports.searchDb =function(){
var Mysql = require('node-mysql-promise');
var mysql = Mysql.createConnection({
    host: 'dm191867.my3w.com',
    user: 'dm191867',
    password: '123',
   // database:'dm191867_db',
});
//SELECT * FROM table;
mysql.table('SalesInfo').field('OrderNO,OrderDate,CustomID,Quantity,Money,OrderStatus').select().then(function (data) {
    return data;
    console.log(data);
}).catch(function (e) {
    console.log(e);
});
}

报错信息

_http_outgoing.js:439
    throw new TypeError('first argument must be a string or Buffer');
    ^

TypeError: first argument must be a string or Buffer
    at ServerResponse.OutgoingMessage.write (_http_outgoing.js:439:11)
    at Server. (c:\Users\lenovo\WebstormProjects\bootstrap\myserver.js:8:13)
    at emitTwo (events.js:87:13)
    at Server.emit (events.js:172:7)
    at HTTPParser.parserOnIncoming [as onIncoming] (_http_server.js:528:12)
    at HTTPParser.parserOnHeadersComplete (_http_common.js:88:23)

刚刚接触nodejs 被搞得头大请大神帮忙！

按照大神的方法改好了，但是遇到了新的问题。我现在mysql.query('XXXXXX')中的sql句是固定的。我想动态生成不同的sql语句，就在searchDb的参数里加了个sqldata。
代码如下：

exports.searchDb =function (sqldata,resultCallback){
var Mysql = require('node-mysql-promise');
var mysql = Mysql.createConnection({
host: 'qdm19.my3w.com',
user: 'qdm19',
password: '123E',
database:'qdm19_db',
});
//SELECT XX FROM table;
mysql.query('SELECT DISTINCT %s,%s,%s,%s,%s,%s FROM %s WHERE %s',sqldata).then(function (data)
{
console.log(data);
resultCallback(null,data);
}).catch(function (e) {
console.log(e);
resultCallback(e);
});
}

其中sqldata是个数组

var sqldata=
[ 
 'OrderNO',
 'DATE_FORMAT( OrderDate , "%Y-%m-%d")OrderDate',
 'c.CustomName',
 '(select count(Quantity) from SalesInfo where OrderNo=s.OrderNO)Quantity',
 '(select sum(Money) from SalesInfo where OrderNo=s.OrderNO)Money',
 'OrderStatus',
 'SalesInfo as s left join Customer as c on s.CustomID=c.CustomNo',
 '1=1'
]

换成这种形式以后第一次查询是没有问题的再点一次查询就会报错说sql句有问题。。

4 个回答

虽然我没用过，但是你应该把promise返回吧？
```
return mysql.table('SalesInfo').xxxxx
```
然后
```
db.searchDb().then(function(data) {

})
```
2022-11-04 06:53 回答

牛奶姆姆_592
return 的数据在回调函数中、传回来应该是undefined吧、可以把回调传进去、

2022-11-04 07:01 回答

RebeccaLd
学习一下async库

2022-11-04 07:06 回答

蜗蜗家的逆时针

var resu;
var db = require("./dbs.js?1.2.1");
var http=require("http");
var server=http.createServer(function(req,res){
    if(req.url!=="/favicon.ico"){
        db.searchDb(function(error,resultData){
                                  res.writeHead(200,{"Content-Type":"text/plain","Access-Control-Allow-Origin":"*"});
        if(error){
            //返回错误信息
            res.write(error);
        }else{
            res.write(resultData);
        }
        
        res.end();
        });
    }
    
});
server.listen(1338,"localhost",function(){
    console.log("开始监听...");
});

数据库查询

exports.searchDb =function(resultCallback){
var Mysql = require('node-mysql-promise');
var mysql = Mysql.createConnection({
    host: 'dm191867.my3w.com',
    user: 'dm191867',
    password: '123',
   // database:'dm191867_db',
});
//SELECT * FROM table;
mysql.table('SalesInfo').field('OrderNO,OrderDate,CustomID,Quantity,Money,OrderStatus').select().then(function (data) {
    //return data;
    console.log(data);
    resultCallback(null,data);
}).catch(function (e) {
    console.log(e);
    resultCallback(e);
});
}

2022-11-04 07:12 回答

裂爆传说_818

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node.js - nodejs查询数据库 执行顺序不太对。。怎么同步查询

刚刚接触nodejs 被搞得头大 请大神帮忙！

node.js - nodejs查询数据库执行顺序不太对。。怎么同步查询

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