node.js/javascript: Simple Database Query in Node check empty

Question

i have a Simple Query in node.js. But i can not handle the error or empty. I have tried:

isempty, =="", =="undefined"

con.query("SELECT id FROM users WHERE secretkey = 
'"+connection_on_obj.secretkey+"' AND id = 
 '"+connection_on_obj.userid+"' LIMIT 1",

 function (err, result, fields) {

 if(err) {

 console.log("ERROR");

 }else{

  if(result[0].id) {

    console.log("OK");

   }else{

   console.log("NO USER");

   }

 }
});

I become in the most cases the error: Cannot read property 'id' of undefined

Federkun · Accepted Answer · 2018-04-01 01:09:18Z

2

If you want check if you got an empty list,just check the size of the array.

if (result.length === 0) {
    // "error", no results found.
}

answered Apr 1, 2018 at 1:09

Federkun

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3 Comments

Burhan Over a year ago

Works not for me :-(. result[0].id.length===0 ---

/sockets/node_modules/mysql/lib/protocol/Parser.js:80                                                                                                             throw err; // Rethrow non-MySQL errors ^  TypeError: Cannot read property 'id' of undefined     at Query._callback (/sockets/index.js:75:26)

Federkun Over a year ago

result.length, not result[0].id.length.

Burhan Over a year ago

Works now fine. Thanks

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