是否需要为我的select语句更改变量的名称？

I've developed a habit of renaming my SELECT statement variable and I'm interested to know if it is necessary or not.

Here some typical code that I use:

$sql = ("SELECT * FROM tbl_one");

if(!$result_sql = $mysqli->query($sql))
{
// Error code here
}

while($a = $result_sql->fetch_assoc())
{
echo $a;
}

$sql2 = ("SELECT * FROM tbl_two");

if(!$result_sql2 = $mysqli->query($sql2))
{
// Error code here
}

while($b = $result_sql2->fetch_assoc())
{
echo $b;
}

For some reason I'm afraid there will be issues if I reuse the same $sql variable over again unless I rename it.

It's always good to have a different different variable for each statement you have as per coding standards even though PHP does not mind using same variable again and again.

It's just a string, so you shouldn't care. Its fine to use the same variable again if you don't need the previous value anymore.

Theoretically I opt not to reuse variable names for this sort of code, because of the risk of accidentally not overwriting one of them and getting strange results.

Then again, that problem doesn't go away just because you try to force yourself to remember to increment a number stuck on the end of the variable name.

Over time, as my code has improved, I've found that I very rarely need or want to execute multiple MySQL queries within a single PHP function, so the problem goes away entirely.

tl;dr: If I had a gun to my head, though... yes, I'd probably do it the same way you did. It's entirely subjective, though.