使用旧的 mysql_* API 从特定行中选择特定列 [英] Select specific column from specific row using old mysql_* API

问题描述

我的 SQL 数据库中有一个表，该表有两个字段，一个用于 ID，另一个用于整数.我想获取整数字段中的值，其中 id 等于我传入的特定数字.id 字段称为id".并且整数字段称为loglevel".这是我得到的代码，但它没有给我想要的结果.

I've got a table in my SQL Database, and the table has two fields, one for an id, and the other for an integer. I want to grab the value in the integer field where the id is equal to a specific number I pass in. The id field is called "id" and the integer field is called "loglevel". This is the code I've got, but it doesn't give me the desired result.

$result = mysql_query("SELECT loglevel FROM Logs WHERE id='$number'");
echo "Pulled from SQL: " . $result;

这个输出是

Pulled from SQL: Resource id #2

你能帮我把输出变成2"吗?如果 SQL 表中的值为 2?

Can you help me so the output is "2" if the value in the SQL table is 2?

推荐答案

您需要使用 mysql_fetch_assoc() 或 mysql_fetch_array()(或其他).$result 由 mysql_query() 返回，是结果资源，而不是实际的行集:

You need to fetch your result using mysql_fetch_assoc(), or mysql_fetch_array() (or others). $result as returned by mysql_query(), is a result resource, not an actual rowset:

$result = mysql_query("SELECT loglevel FROM Logs WHERE id='$number'");

// If the query completed without errors, fetch a result
if ($result) {
  $row = mysql_fetch_assoc($result);
  echo $row['loglevel'];
}
// Otherwise display the error
else echo "An error occurred: " . mysql_error();

当您期望返回多行而不是单行时，请在 while 循环中获取它们.mysql_fetch_assoc() 文档.

When you are expecting multiple rows returned rather than just one, fetch them inside a while loop. There are many examples of this in the mysql_fetch_assoc() documentation .

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