单引号，双引号和“未定义索引” [英] single quotes, double quotes and "undefined index"

问题描述

我正在尝试编写干净的代码，但在决定引用数组索引时什么时候一直无法确定

什么时候引用数组索引？什么时候不引用。


有时当我引用时双引号内的数组索引我

得到一个关于空白空间的错误（给我最好的记忆）


其他时候我得到一个未定义的索引通知下面：


注意：未定义索引：last_reminder_id in ...


第二行（在此帖子中包含第3行

是错误消息中列出的那个：


$ sql =" SELECT * from notes

其中recall_date''0' '和'recall_date< =''$ now''和id>

''$ _SESSION [last_reminder_id]''" ;;


什么是正确的语法和/或任何人都可以指向一个

参考来解释这个吗？


bill

解决方案

sql =" SELECT * from notes

where recall_ date''0''和recall_date< =''

now''和id>

''

< blockquote> _SESSION [last_reminder_id]''" ;;


什么是正确的语法和/或任何人都可以指向我的

引用来解释这个？


账单

I am trying to write clean code but keep having trouble deciding
when to quote an array index and when not to.

sometimes when I quote an array index inside of double quotes I
get an error about enased whitespace (to my best memory)

AT other times I get an undefined index notice as below:

Notice: Undefined index: last_reminder_id in...

the 2nd line (which wraps to the 3rd in this posting
is the one listed in the error message:

$sql = "SELECT * from notes
where recall_date ''0'' and recall_date <= ''$now'' and id >
''$_SESSION[last_reminder_id]''";

what is the correct syntax and/or can anyone point me at a
reference that will explain this ?

bill

解决方案

sql = "SELECT * from notes
where recall_date ''0'' and recall_date <= ''

now'' and id >
''

_SESSION[last_reminder_id]''";

what is the correct syntax and/or can anyone point me at a
reference that will explain this ?

bill

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