What will happen if this code is mistaken? What to do with it

What will happen if this code is mistaken?
The first is right. The second is wrong, with no bean number between fields
What happens if you do it in the second way?

The first type:
{
$r = $empire->fetch1 ("select id,ddd,aaa,bbb from {$dbtbpre}ecms_". $class _r[$classid][tbname]. "Where id= ' $id ' and Classid= ' $classid ' limit 5 ');
if ($r [id])
{
?>
document.write (' ', ' ', ' ');

}
}
Else
{
?>
document.write (' Login to view ');
}
Db_close ();
$empire =null;
?>

The second type:
{
$r = $empire->fetch1 ("Select Id,ddd aaa bbb from {$dbtbpre}ecms_". $class _r[$classid][tbname]. "Where id= ' $id ' and Classid= ' $classid ' limit 5 ');
if ($r [id])
{
?>
document.write (' ', ' ', ' ');

}
}
Else
{
?>
document.write (' Login to view ');
}
Db_close ();
$empire =null;
?>

Where DDD AAA BBB is the controlled field

------Solution--------------------
It doesn't matter!
Depends on different databases
------Solution--------------------
Nothing, it could be wrong. May be seen as an alias
------Solution--------------------
discuss

It doesn't matter!
Depends on different databases

------Solution--------------------
Select ID,DDD AAA BBB This situation can go wrong.
Select ID,DDD AAA treats AAA as a DDD alias

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