php SELECT id FROM table_name WHERE column = $variable
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SELECT id FROM table_name WHERE column = $variable
提问by Michael
I'm trying to retrieve the id number of a record to use as a variable elsewhere. I only want the id from a record that has a particular value in another column. here is my code:
我正在尝试检索记录的 ID 号以用作其他地方的变量。我只想要在另一列中具有特定值的记录中的 id。这是我的代码：
$result = mysql_query("SELECT id FROM order WHERE orderNumber = '$orderNumber'") or die (mysql_error());
$id = $result;
When I test I get: SQL syntax; check the manual that corresponds to your MySQL server versi0on for the right syntax to use near 'order WHERE orderNumber = '5b0ea3'
当我测试时，我得到： SQL 语法；检查与您的 MySQL 服务器版本相对应的手册，了解在 'order WHERE orderNumber = '5b0ea3' 附近使用的正确语法
Any ideas?
有任何想法吗？
回答by andrewsi
SELECT id FROM order WHERE orderNumber = '$orderNumber
ORDER is a reserver word in SQL; I'd recommend you change the name of the column to something else.
ORDER 是 SQL 中的保留字；我建议您将列的名称更改为其他名称。
If you really can't, then you can escape column and table names with backticks:
如果你真的不能，那么你可以用反引号转义列和表名：
SELECT `id` FROM `order` WHERE `orderNumber` = '$orderNumber'
And also see the comments about stopping using mysqli_functions - they're insecure, and being deprecated.
还可以查看关于停止使用mysqli_函数的评论——它们不安全，并且已被弃用。
回答by mpratt
Since ORDERis a reserved word, you must use backticks on your sql query. And after that use the mysql_fetch_associn order to get the id.
由于ORDER是保留字，因此您必须在 sql 查询中使用反引号。然后使用mysql_fetch_assoc来获取 id。
$result = mysql_query("SELECT `id` FROM `order` WHERE `orderNumber` = '$orderNumber'") or die (mysql_error());
$row = mysql_fetch_assoc($result);
$id = $row['id'];
On the other hand, you should be using PDOor Mysqli, the mysql_*functions are deprecated and considered a bad practice.
另一方面，您应该使用PDOor Mysqli，这些mysql_*功能已被弃用并被认为是一种不好的做法。
If you plan on keep using mysql_query, at least make sure to sanitize the $orderNumbervariable with mysql_real_escape_String.
如果你打算继续使用mysql_query，至少确保$orderNumber用mysql_real_escape_String清理变量。
回答by ahmad haboul
mysqli_query($connection,"SELECT `id` FROM `order` WHERE `orderNumber` = '$orderNumber'");
as you see you must include $connection.
如您所见，您必须包含 $connection。
回答by webdevil
Built using custom database class with query function, but the SQL query works
使用具有查询功能的自定义数据库类构建，但 SQL 查询有效
$id = 1;
$database->query("SELECT * FROM tbl_post WHERE post_id = '$id'");
