MySQL Affected_Rows() returns number of rows selected instead of false for SELECT statements

[mariobernheim]

Hi,

<?php
$sql = "SELECT * from subscribers WHERE number='".$number."' AND service_id='".$service_id."' LIMIT 1";
$rs  = $Conn->execute($sql);
if ($Conn->Affected_Rows()) {
    $active = $rs->fields['active'];    
    
    echo return_json_status("3","Number $number is subscribed to $service_id and is set active=$active");
    die("");
}
?>

For some reason this works... however, from the ADOdb Documentation, its not supposed to:

https://adodb.org/dokuwiki/doku.php?id=v5:reference:connection:affected_rows

Database: MySQL 5.7
Driver: Mysqli
PHP Version: PHP 7.0.33
ADOdb Version: V5.18

[mnewnham]

Database? Driver? PHP Version? ADOdb Version?

[mariobernheim]

Database: MySQL 5.7
Driver: Mysqli
PHP Version: PHP 7.0.33
ADOdb Version: V5.18

[mariobernheim]

For references... I just tested these too

PHP Version: 7.2.25
ADOdb Version: v5.20.14

I do SELECT * from table limit 1 and Affected_Rows(); returns 1

[mnewnham]

This is due to a change in the behavior of the underlying mysqli_affected_rows(), which according to The PHP documentation, now acts as mysqli_num_rows() for SELECT statements. In order to maintain cross-database compatibility, we need to suppress this behavior.

[mariobernheim]

Thanks, so for all purposes, we should be able to use Affected_Rows(); on all SELECT's as well and can consider it reliable?

[mnewnham]

No, you should not, because no other database supports it. The code will be changed so that it conforms to our standard, i.e. It will return false for SELECT statements

[mariobernheim]

Should we use RecordCount(); instead?

[mnewnham]

absolutely

[peterdd]

Maybe the example on https://adodb.org/dokuwiki/doku.php?id=v5:reference:connection:affected_rows should include an insert query too, ideally with 2 or 3 row values in the insert query to have a number >1 on success.

And maybe remove the select example there to avoid confusion or add an explanation. It is unclear from the example if table act contains just no rows or means 'error', so the 'Return false' there might be misinterpreted.

Otherwise this issue can be closed?

[mnewnham]

If you want to create a small example and paste it in here, I will happily update the documentation with it