为什么“while”循环总是用于迭代mysql_fecth_array（）函数的结果？

Question

Why don't people use for ,foreach or do..while() and why omit increment counter in while?

`<?php  while ( $fa = mysql_fetch_array($sel1) )//uesd mysql_fetch_array() function in while loop
    { 
          echo  $fa['cid'];//display client id 
    }

// while Syntax in w3school give to used this

 $x = 1; 

 while($x <= 5) {
     echo "The number is: $x";
     $x++;
 }  
?>//show why we don't used mysql_fecth_array() like this 

Answer 1

This is kind of dated information. In one way you're asking a question that is just accepted along the community. It is understood better that while I have information to show ... do something. You generally wouldn't say foreach of these items ... do something though you could. However, the other problem is mysql_fetch_array returns FALSE if there are no more rows. This would not work in a foreach because it is not an array. A for would also fail because to check for the finishing of a for you have to go to some point and end.. FALSE is not a valid point of check (that I have ever tried or used).

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@Michael Berkowski Adds:

As of PHP 5.4+, the mysqli_result class does have Iterator support, meaning you can do $result = mysqli_query(...); and subsequently foreach ($result as $row) {...} and it will fetch associative arrays

Though this isn't to be said the most commonly used form which is why we have the question.

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You could do...while but why would you. You don't have most the information that you're going to need from the fetch array.

While is accepted and generally better. Doesn't fail and has a fall back if the mysql fails any way.

Lastly... don't use mysql_* anymore. Switch to mysqli_*. Safer.. smarter.. better.