php - 无法显示查询结果--php/mysqli

<form action="send_post.php" method="post">
   <p>A: <input type="text" name="A">
   <p>B: <input type="text" name="B">
   <p><input type="submit">
</form>
<?php
    $db = "localhost"; $usr = "blah1"; $pword = "blah2"; $dbname = "blah3";
    -----connects to server ok -------
    $A = mysqli_real_escape_string($conn, $_POST['A']);
    $B = mysqli_real_escape_string($conn, $_POST['B']);
    $query="SELECT * FROM blah4 where A=$A and B=$B";
    $sql=mysqli_query($conn, $query);
    echo $sql;
    $conn->clos();
?>

显示数据库中的数据需要什么？

最佳答案

您的查询字符串格式不正确

<form action="send_post.php" method="post">
   <p>A: <input type="text" name="A"> </p>
   <p>B: <input type="text" name="B"> </p>
   <p><input type="submit">    </p>
</form>
<?php
    $db = "localhost"; $usr = "blah1"; $pword = "blah2"; $dbname = "blah3";
    -----connects to server ok -------
    $A = mysqli_real_escape_string($conn, $_POST['A']);
    $B = mysqli_real_escape_string($conn, $_POST['B']);
    $query="SELECT * FROM blah4 where A='$A' and B='$B'";
    $sql=mysqli_query($conn, $query);
    echo $sql;
    $conn->close();
?>

要么

  $query="SELECT * FROM blah4 where A='".  $A ,"' and B='" .$B ."'";

您还没有关闭</p>

和

$conn->close();