This condition 1 and (0 OR condition 2) How logical operations are understood

This condition 1 and (0 OR condition 2) logical operation how to understand?
Recently encountered such a problem, is about the logical operation, see:
Condition 1 and (0 OR condition 2)
If there is no keyword, then the latter part is (0)
Condition 1 and (0), that is not true, no query results returned, no input keywords.
If there is, then:
Condition 1 and (0 OR condition 2)
is actually
Condition 1 and (condition 2)
I have written a test code:
$a = 3;
$b = 0;
if ($a and (1 OR $b))
{
Print $a. $b;
}
Else
{
Print "false";
}
?>
I write the above and (0 or $b) intentionally into and (1 or $b)) and the test results are as follows:
30
A netizen pointed out that and (1 and $b)) or and (0 or $b)), when the condition is and, the front plus 1, when the condition is OR, plus 0 will not affect the result set.
But I deliberately write the opposite, the results of the test 30, for this expression still do not understand, also do not know where the idea card, of course, if written in $ A and (0 OR $b) will be output false, because only one side value is true, but still do not understand the difference is where, everyone give twos good? Thank you so much.

------Solution--------------------
1and$b need two conditions are set up
1or$b because it has been judged that the front is 1, and the back is not judged
0or$b Front is O is not established, so continue to judge whether $b is established.

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