in_array仅查找第一个值

Question

What I'm trying to do is to assign variables based upon a sql query. The field "County" is a varchar containing the names of Counties.

 $sql="SELECT County from GAINLP WHERE SpeciesName LIKE '%Actias_luna%'";
    ($result=mysqli_query($connect,$sql));
    $row=mysqli_fetch_array($result,MYSQLI_ASSOC);

    if (in_array("Porter", $row))  {
                $Porter='Present';
                    }
                else {$Porter='Not Present';
                     };
    echo $Porter;

What happens is that in_array is only detecting the very first county in the array. If I echo $row, I get this:

OwenPikeParkeOwenOwenScottMorganGreeneHendricksLawrenceSt.JosephWashingtonVigoMorganOwenDuboisJeffersonSwitzerlandMadisonGreeneFayetteMarionOrangeParkeClarkJeffersonFayetteFountainMontgomeryHendricksHowardOwenElkhartMarionHendricksWashingtonTippecanoePutnamWashingtonBrownHendricksJenningsOwenWhitleyKosciuskoPorterVermillionHendricks

If I assign the needle as "Owen," echo $Porter returns "Present". All other values echo "Not Present." If I loop it, even "Owen" returns "Not Present" to $Porter. What am I doing wrong here?

This also does not work:

$sql="SELECT County from GAINLP WHERE SpeciesName LIKE '%Actias_luna%'";
    ($result=mysqli_query($connect,$sql));
    while ($row = mysqli_fetch_array($result,MYSQLI_ASSOC)) {

    if (in_array("Porter", $row))  {
                $Porter='Found it';
                    }
                else {$Porter='Didn\'t Find it';
                }};
    echo $Porter;

Answer 1

mysqli_fetch_array only fetches one row. Use while loop to go over all rows:

while ($row = mysqli_fetch_array($result,MYSQLI_ASSOC)) {

If you don't want to check per row but want to check if the value exists in any of the rows use mysqli_fetch_all :

$sql="SELECT County from GAINLP WHERE SpeciesName LIKE '%Actias_luna%'";
$result=mysqli_query($connect,$sql);
$rows=mysqli_fetch_all($result,MYSQLI_ASSOC);
if (in_array("Porter", $rows))  {
    $Porter='Present';
} else {
    $Porter='Not Present';
};
echo $Porter;

Answer 2

the line

$row=mysqli_fetch_array($result,MYSQLI_ASSOC);

will only retrieve the first row of the database.

If you want to check every row to see if ANY of them are Porter, then you will need to set the flag to a default of "no", loop your results, and set the flag if you find it:

$Porter="Not Present";
while($row = mysqli_fetch_array($result,MYSQLI_ASSOC)){
    if($row['County'] == "Porter"){
        $Porter = "Present";
    }
}

echo $Porter;

(this is just a basic example; you can optimize it farther by breaking out of the loop when you first find the result for example, but this will do the job)