在另一个MySQL查询中使用一个MySQL查询的结果作为变量

Question

I'm trying to show the result HTML table based on team name

I'm able to echo right team name but unable to use it into a variable in my 2nd query I'm not able to find out what I'm doing wrong here why the query result is not visible. do I need to change something in my code?

<?php
include_once("connection.php");

$sql = "SELECT TeamName FROM `superuser` WHERE id = '303016'";
$queryRecords2 = mysqli_query($conn, $sql) or die("error to fetch employees data");

while ($row2 = $queryRecords2->fetch_assoc()) {
    echo $row2['TeamName']."<br>";
}

if(isset($_POST['search']))
{
    $valueToSearch = $row2['TeamName'];
    $valueToSearch2 = $_POST['valueToSearch2'];
    $valueToSearch3 = $_POST['valueToSearch3'];
    $sql = "SELECT * FROM `dailydata` WHERE TeamName = '".$valueToSearch."' and Date BETWEEN '".$valueToSearch2."' AND '".$valueToSearch3."'";
    $queryRecords = mysqli_query($conn, $sql) or die("error to fetch employees data");
}
else {
    $sql = "SELECT * FROM `dailydata` WHERE TeamName = ''";
    $queryRecords = mysqli_query($conn, $sql) or die("error to fetch employees data");
}

?>          

Answer 1

For security purposes you should use prepared statements or even better you should use PDO instead of mysqli.

to fix this issue simply assign the value of $valueToSearch variable inside the loop.

<?php
include_once("connection.php");

$sql = "SELECT TeamName FROM `superuser` WHERE id = '303016'";
$queryRecords2 = mysqli_query($conn, $sql) or die("error to fetch employees data");

$valueToSearch;
while ($row2 = $queryRecords2->fetch_assoc()) {
    $valueToSearch = $row2['TeamName'];
}

if(isset($_POST['search']))
{
    $valueToSearch2 = $_POST['valueToSearch2'];
    $valueToSearch3 = $_POST['valueToSearch3'];
    $sql = "SELECT * FROM `dailydata` WHERE TeamName = '".$valueToSearch."' and Date BETWEEN '".$valueToSearch2."' AND '".$valueToSearch3."'";
    $queryRecords = mysqli_query($conn, $sql) or die("error to fetch employees data");
}
else {
    $sql = "SELECT * FROM `dailydata` WHERE TeamName = ''";
    $queryRecords = mysqli_query($conn, $sql) or die("error to fetch employees data");
}

?>