javascript - results.length is not give the correct output for MySQL query?

Question

Why the length of result of MySQL query is not correct? The query is just count the number of message column in database and print the length.

the code:

connection.query("SELECT COUNT(message) as total FROM `counter`", (err, results) => {
    if(err) throw err;
    console.log(results);
    console.log("the length of result:", results.length);

the output:

[ RowDataPacket { total: 4 } ]
the length of result: 1

The correct length is 4 not 1.

How to correct that, please?

question from:https://stackoverflow.com/questions/65875718/results-length-is-not-give-the-correct-output-for-mysql-query

Answer 1

results contains the rows returned as an array. Since you're using SELECT COUNT(message), you're querying for the count of messages, which returns one row. This one row contains the result, which is an object of shape { total: 4 } - where the total comes from the as total part of your SQL query.

To get the actual result, check that results.length > 0 and then you can access results[0].total:

if (results.length > 0) {
  console.log('Total:', results[0].total)
} else {
  throw new Error('No results returned from query!')
}