零和NULL [英] Zero and NULL

问题描述

我有以下开关声明：


开关（$ record-> sub_page）{

case -1：

$ this-> page = 6;

$ error_message =''< center>您似乎已经完成了

表格。< / center> '';

休息;

案例0：

$ this-> page = 5;

ff_query （" UPDATE #__ gateway_form_1 SET`sub_page` = -1 WHERE

userid = $ my-> id和`expiry_date` =''$ expiry_date''"）;

休息;

默认：

做其他事情

}


$ record-> sub_page可以为NULL。如果它是NULL，那么0

的情况似乎开始了。我真的需要在

$ record-> sub_page为NULL或+ ve值时发生默认操作。


但是如果我这样做：


开关（$ record-> sub_page）{

case -1：

$ this-> page = 6;

休息;

case NULL：

做其他事情;

休息;

案例0：

$ this-> page = 5;

break;

默认：

做某事否则;

}


然后交换机设法告诉NULL和零之间的区别。


php将NULL视为0是否正确？

有人能建议一个好的修复吗？


TIA

问候

Paul

I have the following switch statement:

switch ($record->sub_page) {
case -1:
$this->page = 6;
$error_message = ''<center>You appear to have already completed the
form.</center>'';
break;
case 0:
$this->page = 5;
ff_query("UPDATE #__gateway_form_1 SET `sub_page`=-1 WHERE
userid=$my->id and `expiry_date` = ''$expiry_date''");
break;
default:
do something else
}

The value of $record->sub_page can be NULL. If it is NULL, the case for 0
seems to fire. I really need the default action to happen when
$record->sub_page is NULL or a +ve value.

However if I do:

switch ($record->sub_page) {
case -1:
$this->page = 6;
break;
case NULL:
do something else;
break;
case 0:
$this->page = 5;
break;
default:
do something else;
}

then the switch manages to tell the difference between a NULL and a zero.

Is it correct that php treats NULL as 0?
Can anyone suggest a good fix?

TIA
Regards
Paul

推荐答案

record-> sub_page）{

case -1：

record->sub_page) {
case -1:

this-> page = 6;

this->page = 6;

error_message =''< center>您似乎已经完成

表格。< / cent呃>'';

休息;

案例0：

error_message = ''<center>You appear to have already completed the
form.</center>'';
break;
case 0:

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