How to determine whether the query result is empty in php

php method to determine whether the query result is empty: 1. Use the sql method, the code is [select count(people) c from people where people='Lele']; 2. Use the php method, the code is [$p=$_POST['p'];].

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php method to determine whether the query result is empty:

1,

select count(people) c from people where people='乐乐'

The above sql is the principle

2,

php utilization code

<?php 
$p=$_POST[&#39;p&#39;];
$cnx = new PDO("odbc:Driver={SQL Server};Server=;Database=;",&#39;&#39;,&#39;&#39;);
$ps=$cnx->query("select count(people) c from people where people=&#39;".$p."&#39;");
foreach($ps as $s){
if ($s[&#39;c&#39;]==&#39;0&#39;){
echo "用户可用";
}else{
echo "此用户名已存在";
}
} 
?>

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