INSERT query produces "Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given"

Question

I am confused about why I am received the following message:

mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given

This question is different from previous queries because my query actually executes correctly (values were indeed entered into the database). So, I would expect MySQL to return a result set and NOT A BOOLIAN.

Below is my function:

function join_main_newsletter($firstName = null, $email)
{
    global $dbc;
    $valuesEntered = "values entered";

    $insert = "INSERT INTO newsletter (first_name, email ) VALUES ('name', 'testemail@yahoo.com')";

    $R3 = mysqli_query($dbc, $insert) or trigger_error("Query Failed! SQL: $sql - Error: " . mysqli_error(db_conx), E_USER_ERROR);
    if (mysqli_num_rows($R3) == 1) {
        return $valueentered;
    } else {
    }
}

And here is part of the results from the error:

[valuesEntered] => values entered
    [insert] => INSERT INTO newsletter (first_name, email ) 
                  VALUES ('name', 'testemail@yahoo.com')
    [R3] => 1

this is different. my query is working; i.e values are entering into the database. so, i don't have a fault in my query — andreea115, Oct 29 '13 at 13:58

score 4 · Accepted Answer · edited Jan 20 '21 at 20:05

4

The mysqli_num_rows() function returns the number of rows in a result set. For insert, update and delete use mysqli_affected_rows

edited Jan 20 '21 at 20:05

Dharman

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answered Oct 29 '13 at 14:02

Mihai

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score 1 · Answer 2 · edited Jan 20 '21 at 20:06

1

Use mysqli_affected_rows() - Number of rows affected by the last INSERT, UPDATE, REPLACE or DELETE query.

edited Jan 20 '21 at 20:06

Dharman

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25
85
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answered Oct 29 '13 at 14:03

Krish R

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*What* may be the reason? – gen_Eric Oct 29 '13 at 14:05
What should be the result of this? If `mysqli_num_rows()` fails at the first place, because it was an `INSERT`, not a `SELECT`, your code is no help at all. – glglgl Oct 30 '13 at 07:44

INSERT query produces "Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given"

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