array_unique在PHP中不起作用？

I have got a table in my MySql database:

我的MySql数据库中有一个表:

  pageid   | text
-----------+----------
    1      | test
-----------+----------
    2      | example
-----------+----------
    3      | another
-----------+----------
    1      | example1

and this PHP code:

这个PHP代码:

$query = "SELECT pageid FROM test";
$result = mysql_query($query);
while($row = mysql_fetch_array($result))
  {
  $id = $row['pageid'];
  $id1 = array($id);
  $id2 = array_unique($id1);
  foreach ($id2 as $value)
    {
    echo $value . "<br>";
    }
  }

But it returns:

但它返回:

I would like to make the pageids unique. So I would like to echo out the number 1, once. Like this:

我想使pageids独一无二。所以我想回答1号,一次。喜欢这个:

1
2
3

So what am I doing wrong? How could I achieve what I want?

那么我做错了什么?我怎么能实现我想要的?

Thanks in advance...

提前致谢...

[I know that this code doesn't make much sense, but this is just a demo for this question and I have a much more complicated code :) ]

[我知道这段代码没有多大意义,但这只是这个问题的一个演示,我有一个更复杂的代码:)]

3 个解决方案

#1

Of course, the real answer in this situation is to select distinct records to begin with:

当然,在这种情况下,真正的答案是选择不同的记录开头:

$query = "SELECT DISTINCT pageid FROM test";

But as to why your code doesn't work...

但至于为什么你的代码不起作用......

You are declaring $id1 as an array, but not appending to it. Instead you're just creating a 1 element array each time. Instead, append all results then call array_unique()

您将$ id1声明为数组,但不附加到它。相反,你每次只创建一个1元素数组。相反,追加所有结果然后调用array_unique()

$query = "SELECT pageid FROM test";
$result = mysql_query($query);

// Declare array first
$id1 = array();
while($row = mysql_fetch_array($result))
  {
  $id = $row['pageid'];
  // Append to the array...
  $id1[] = $id;
  }

// Call array_unique() outside the loop:
$id2 = array_unique($id1);
foreach ($id2 as $value)
{
  echo $value . "<br>";
}

#2

You could do it in your SELECT by doing something like SELECT DISTINCT pageid FROM test or by using GROUP BY like this:

您可以通过执行SELECT DISTINCT pageid FROM test或使用GROUP BY之类的操作在SELECT中执行此操作:

SELECT pageid FROM test WHERE 1 GROUP BY pageid

#3

You can use Distinct keyword in your sql query.That will return you the unique vaues of Page

您可以在sql查询中使用Distinct关键字。这将返回页面的唯一值

#1