在Php中获取行数

Question

we have a table usersandgroups and it has four rows.I am trying to fetch the row count as per group id but it is returning 1 for every group id but it has many rows......one more point when i remove where clause condition even then it is returning 1...that means it is always returning 1.

<?php

 require_once("db_connect.php");

 $gp_id = $_POST["GP_ID"];

 $query = "SELECT COUNT(*) FROM USER_ANDGROUPS WHERE GP_ID = '$gp_id';";

 $res = mysqli_query($con,$query);


 if(mysqli_num_rows($res)>0)
 {
    $row_cnt = $res->num_rows;
     echo $row_cnt ;
 }
 else
 {
   echo "false";
 }

?>

I am trying to fetch the row count as per group id but it is returning 1 for every group id but it has many rows......one more point when i remove where clause condition even then it is returning 1...that means it is always returning 1.

Answer 1

SELECT COUNT(*) FROM will always return a single row which has the complete record number in itself

Change SELECT COUNT(*) FROM to SELECT * FROM and you are good to go

Note: Your code is wide open for SQL INJECTION. so use prepared statements to prevent from that.

mysqli::prepare