use global variable in node js query mysql

Question

How can i use global variable in query result function? Here is an example:

var arr = [];
var sql = "my sql code";
conn.query(sql, function(err, result){
   arr.push(result[0]);
});
console.log(arr);   // Here the result value must be displayed.

Thanks in advance.

use Promise concept or defer concept of q module – Manvendra Priyadarshi May 11 '18 at 12:13 — Manvendra Priyadarshi, May 11 '18 at 12:13

score 0 · Answer 1 · answered May 11 '18 at 11:50

0

conn.query is an asynchronous method and will call the function you are passing in on completion.

Due to this, your console.log statement is executed before the global variable has been set with the result.

To solve this, place your console.log statement within the callback:

conn.query(sql, function(err, result){
   arr = result;
   console.log(arr);
});

answered May 11 '18 at 11:50

hairmot

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Thanks. What if I put a variable instead of console.log? I need to use it on the next lines (out of callback function) – Jake May 11 '18 at 12:00

use global variable in node js query mysql

1 Answers1