what is the difference between AND && OR ||

im trying to compare 4 variables so it must be look like this

if ($a == $b and $c ==$d) or ($e==$f and $g==$h)

but the result is always wrong

 

thanks for reply but didnt work

error: Parse error: syntax error, unexpected T_BOOLEAN_OR

 

You need to put it all in parentheses

if ( ($a == $b and $c ==$d) or ($e==$f and $g==$h) )

PHP:

 

Bit more than that, actually:

if ( ( ( $a == $b ) and ( $c ==$d ) ) or ( ( $e==$f ) and ( $g==$h ) ) )

PHP:

That works, but you actually MEAN:

if ( ( ( $a == $b ) && ( $c ==$d ) ) || ( ( $e==$f ) && ( $g==$h ) ) )

PHP:

 

Simple..

if ($a == $b && $c == $d || $e==$f && $g==$h){

//match
}

PHP:

 

That's not at all true.

The PHP operators 'and' and 'or' are identical to '&&' and '||' except that they have different association precedence. Most significantly for typical uses, '||' associates before assignment operators, while 'or' associates after them.

For example, you can do:

$stmt = mysql_query($query) or die(mysql_error());

Code (markup):

and get the desired outcome (fall through and evaluate what's after the 'or' only if the assignment that comes before it evaluates as false) but if you tried to do:

$stmt = mysql_query($query) || die (mysql_error());

Code (markup):

then you'd get an undesired outcome because that is equivalent to:

$stmt = (mysql_query($query) or die(mysql_error()));

Code (markup):

which would have a boolean result which makes $stmt useless.

For bitwise comparisons you'd use the bitwise operators like '&' and '|'.