问题描述
我对 PHP 和 MySQL 还是很陌生,我就是想不通.我在论坛上到处搜索,但没有找到我能理解的答案.我最初使用 mysql_fetch_assoc() 但我只能搜索数字并且在搜索字母时也收到错误.我希望我在这里走在正确的轨道上.在此先感谢您的帮助!
I am pretty new to PHP and MySQL and I just can't figure this one out. I have searched all around the forum but haven't found an answer I can make sense of. I originally was using mysql_fetch_assoc() but I could only search numbers and I received errors when searching for letters as well. I hope I am on the right track here. Thank you in advance for all your help!
$con = mysqli_connect($hostname,$username,$password) or die ("<script language='javascript'>alert('Unable to connect to database')</script>"); mysqli_select_db($con, $dbname); if (isset($_GET['part'])){ $partid = $_GET['part']; $sql = 'SELECT * FROM $usertable WHERE PartNumber = $partid'; $result = mysqli_query($con, $sql); $row = mysqli_fetch_assoc($result); $partnumber = $partid; $nsn = $row["NSN"]; $description = $row["Description"]; $quantity = $row["Quantity"]; $condition = $row["Conditio"]; }
推荐答案
当您的结果不是结果(而是假")时会发生这种情况.你应该改变这一行
This happens when your result is not a result (but a "false" instead). You should change this line
$sql = 'SELECT * FROM $usertable WHERE PartNumber = $partid';
为此:
$sql = "SELECT * FROM $usertable WHERE PartNumber = $partid";
因为 " 可以解释 $variables 而 ' 不能.
because the " can interprete $variables while ' cannot.
适用于整数(数字),对于字符串,您需要将 $variable 放在单引号中,例如
Works fine with integers (numbers), for strings you need to put the $variable in single quotes, like
$sql = "SELECT * FROM $usertable WHERE PartNumber = '$partid' ";
如果你想/必须使用单引号,那么php不能解释变量,你必须这样做:
If you want / have to work with single quotes, then php CAN NOT interprete the variables, you will have to do it like this:
$sql = 'SELECT * FROM '.$usertable.' WHERE string_column = "'.$string.'" AND integer_column = '.$number.';