Why is there an endless loop between the two database reading methods?

Why is there an endless loop between the two database reading methods? Normal syntax:

 ';} Else {echo 'lishuwrong'. mysql_error ().'
';} $ B = mysql_query ("select * from shoping") or die ('lishudie '. mysql_error (); // Create record set $ assoc = mysql_fetch_assoc ($ B); while ($ assoc) {echo $ assoc ['item _ id']. '----------'. $ assoc ['name'].'
'; $ Assoc = mysql_fetch_assoc ($ B);} mysql_close ($ select);?>

After I rewrite:

 ';} Else {echo 'lishuwrong'. mysql_error ().'
';} // $ B = or die ('lishudie '. mysql_error (); // Create record set $ assoc = mysql_fetch_assoc (mysql_query ("select * from shoping"); while ($ assoc) {echo $ assoc ['item _ id']. '----------'. $ assoc ['name'].'
'; $ Assoc = mysql_fetch_assoc (mysql_query ("select * from shoping");} mysql_close ($ select);?>

Reply to discussion (solution)

$ Assoc = mysql_fetch_assoc (mysql_query ("select * from shoping "));
While ($ assoc)
{
Echo $ assoc ['item _ id']. '----------'. $ assoc ['name'].'
';
$ Assoc = mysql_fetch_assoc (mysql_query ("select * from shoping "));
}
You get the first record of the query result every time.
When will this $ assoc become logical false?

Although programming can have a lot of flexibility, but the basicTheoryIt cannot be changed.

$ Assoc = mysql_fetch_assoc (mysql_query ("select * from shoping "));
While ($ assoc)
{
Echo $ assoc ['item _ id']. '----------'. $ assoc ['name'].'
';
$ Assoc = mysql_fetch_assoc (mysql_query ("select * from shoping "));
}
You get the first record of the query result every time.
When will this $ assoc become logical false?

Although programming can have a lot of flexibility, but the basicTheoryIt cannot be changed.

I seem to understand it a little. I just started learning PHP. thank you! Join us!