如果构造只显示else值 - PHP

Question

Here is my statement:

if($row_x['xfield']==$_POST['x1'] AND $row_x['yfield']==$_POST['y'])
{
   echo "ok";
}
else {
   echo "invalid";
}

When both are not equal to each other, it must display 'invalid' else, 'ok'. But in this case it displays 'invalid' whether it is valid or not.

Any clues to why?

Answer 1

You said 'when BOTH are NOT equal'... implying you would want to use '!=' instead of '==' in your comparisons. See this T/F chart for &&:

--------------
| X | && | Y |
--------------
| F | F  | F |
--------------
| F | F  | T |
--------------
| T | F  | F |
--------------
| T | T  | T |
--------------

The X statement must be true AND the Y statement must be true. In your example

$row_x['xfield']==$_POST['x1']

must be TRUE as well as

$row_x['yfield']==$_POST['y']

But if I read your question you will want to have both statements as FALSE to show 'invalid'. So you'll need to substitute '==' for '!=' in each statement.