如果在获取期间数据为空或空，则PHP Mysqli替换逗号

Have a issue with comma "," when I am fetching the data if the data for selected id is empty then also the coma(,) shows up what i want is if the data is null or empty the "," should not show up which am unable to do.

say I am selecting the data for
id 1 ,2 ,3Where for ID 1 Num is 6789 and ID 2 has no Num and id 3 has 12345

 $query="SELECT  Num FROM euser WHERE UserId IN (SELECT ID FROM master WHERE  aa='aa' And cc='cc')" ;
        $data=mysqli_query($mysqli,$query)or die(mysqli_error());
        $Num = array();
        while($row=mysqli_fetch_array($data)){
            $Num[] = $row['Num'];

        }
        $NumStr = implode(',', $Num);


        echo $NumStr;

    mysqli_close($mysqli);

Present output

6789,,12345

Expecting output

6789,12345

Use isset()

while ($row = mysqli_fetch_array($data)) {
    if (isset($row['Num']) && $row['Num'] != "") {
        $Num[] = $row['Num'];
    }
}
$NumStr = implode(',', $Num);

Replace you code with below code.

Added a check for blank and NULL.

$query="SELECT  Num FROM euser WHERE UserId IN (SELECT ID FROM master WHERE  aa='aa' And cc='cc')" ;
        $data=mysqli_query($mysqli,$query)or die(mysqli_error());
        $Num = array();
        while($row=mysqli_fetch_array($data)){
            if($row['Num'] != '' && $row['Num'] != NULL){
            $Num[] = $row['Num'];
            }    
        }
        $NumStr = implode(',', $Num);    

        echo $NumStr;    
        mysqli_close($mysqli);

 $query="SELECT  Num FROM euser WHERE UserId IN (SELECT ID FROM master WHERE  aa='aa' And cc='cc')" ;
        $data=mysqli_query($mysqli,$query)or die(mysqli_error());
        $Num = array();
        while($row=mysqli_fetch_array($data)){
            $Num[] = $row['Num'];

        }
        $final_arr = array_filter($Num);
        $NumStr = implode(',', $final_arr);

        echo $NumStr;    
        mysqli_close($mysqli);

You just have to use "array_filter" function to remove empty/null values from the array.