PHP 检查 NULL
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PHP Check for NULL
提问by Angel.King.47
Here is the below Code:
这是下面的代码：
$query = mysql_query("SELECT * FROM tablex");
if ($result = mysql_fetch_array($query)){
if ($result['column'] == NULL) { print "<input type='checkbox' />"; }
else { print "<input type='checkbox' checked />"; }
}
If the values are NOT NULLi still get the uncheked box. Am i doing something wrong from above, shoudnt $result['column'] == NULLwork?
如果值是NOT NULL我仍然得到未选中的框。我从上面做错了什么，应该$result['column'] == NULL工作吗？
Any Ideas?
有任何想法吗？
回答by The Chairman
回答by fernyb
How about using
怎么用
if (empty($result['column']))
if (empty($result['column']))
回答by Tomas Markauskas
Make sure that the value of the column is really NULL and not an empty string or 0.
确保该列的值确实为 NULL 而不是空字符串或 0。
回答by Joel
I think you want to use
我想你想用
mysql_fetch_assoc($query)
rather than
而不是
mysql_fetch_row($query)
The latter returns an normal array index by integers, whereas the former returns an associative array, index by the field names.
后者按整数返回一个普通数组索引，而前者返回一个关联数组，按字段名称索引。
回答by Andrew
Sometimes, when I know that I am working with numbers, I use this logic (if result is not greater than zero):
有时，当我知道我在处理数字时，我会使用以下逻辑 ( if result is not greater than zero)：
if (!$result['column']>0){
}
