This question already has an answer here:
In my PHP code I try to get data from my database but I get
"Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given"
as an error.
I found on stackoverflow that this indicates that my SQL query is getting back false. if I copy my sql query into the phpmyadmin sql field everything works just fine.
I tried various different notations (giving 1 and true for the boolean "fährt")
$sql = "SELECT * FROM `$params` WHERE `fährt` = 1" ;
$result=mysqli_query($conn,$sql);
if(mysqli_num_rows($result) != 0){
while($row = mysqli_fetch_array($result)){
echo "<br>".$row[0]."-".$row[1]."-".$row[2]."-".$row[3]."-".$row[4]."-".$row[5];
}
}else{
echo "Fehler";
}
Expected: One entry from my database
Actual output: Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given
UPDATE
So I tried what was said in the comments but it for me it does not explain why it works when I copy it to phpmyadmin. Furthermore it does work without the where clause.
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