Does the correct request manage to be sent to the engine in my case?

Question

MySQL

There is a piece of code in nodejs. Approximately it looks like this:

mysql.query('SELECT * FROM table WHERE id = '+arr[i]+';',  function(err, res){...});
delete arr[i];

The essence of the question: does the correct request have time to be transmitted to the engine? For some reason, every other time I get a zero execution result (the desired string is 100%, I tried to select the same ID.) There is a feeling that the array element is deleted earlier and undefined goes into the request. If after the request to remove delete arr[i]; then everything is fine. When placed delete arr[i]; the same thing happens in callback.

Answer 1

It shouldn't work, because you can't write like that.
If the deletion is not in the callback, then it will work before the request and arr[i] will be undefined.
If in a callback, then by the time the callback is called, a[i] will not be what you would like at all, and "foreign" data will be beaten.
In general, you can not do the same as yours.