node.js - find number of rows in returned mysql result (nodejs)

Question

When using felixge's mysql for node.js, how can I ask the result object for the number of returned rows? I have a rather expensive query so I don't want to run a COUNT(*) first, just to then run a query a second time.

Answer 1

If it's a select query, just take the length of the returned array.

connection.query(sql, [var1,var2], function(err, results) {
    numRows = results.length;
});

If it's an update/delete query, the returned dictionary will have an affectedRows variable.

connection.query(sql, [var1,var2], function(err, result) {
    numRows = result.affectedRows;
});