After sorting php articles, move them forward and backward. if the written statements do not work, I don't know what went wrong?

After sorting php articles, move them forward and backward. if the written statements do not work, I don't know what went wrong? I manually move the document sort forward and backward, but the SQL statement does not seem to work. Which of the following can help you see it?

/* Forward */if ($ result = 'up') {$ sql0 = $ db-> query ("select sort from ". $ db-> table ('product '). "where id = '$ ID'"); $ row = $ db-> fetch_array ($ sql0); if (! $ Row) {$ oldpx = 1;} else {$ oldpx = $ row ['sort '];} if ($ oldpx> 1) {$ db-> query ("update ". $ db-> table ('product '). "set sort = sort + 1 where sort = ". $ oldpx-1); $ db-> query ("update ". $ db-> table ('product '). "set sort = sort-1 where id = ". $ id);} header ("Location: product_list.php \ n"); exit;}/* Move Back */if ($ result = 'drop ') {$ sql1 = $ db-> query ("select sort from ". $ db-> table ('product '). "where id = '$ ID'"); $ row = $ db-> fetch_array ($ s Ql1); if (! $ Row) {$ oldpx = 9999;} else {$ oldpx = $ row ['sort '];} $ sql2 = $ db-> query ("select sort from ". $ db-> table ('product '). "order by sort desc limit 1"); $ rows = $ db-> fetch_array ($ sql2); if (! $ Rows) {$ maxpx = 9999;} else {$ maxpx = $ rows ['sort '];} if ($ oldpx <$ maxpx) {$ db-> query ("update ". $ db-> table ('product '). "set sort = sort-1 where sort = ". $ oldpx + 1); $ db-> query ("update ". $ db-> table ('product '). "set sort = sort + 1 where id = ". $ id);} header ("Location: product_list.php \ n"); exit ;}

Reply to discussion (solution)

Will the sort of the article be not Continuous? if you move forward, you may not modify it to the database record by taking sort-1 as an instruction, then, even if sort + 1 is not larger than the sort in the next article

/* Forward */if ($ result = 'up') {$ sql0 = $ db-> query ("select sort from ". $ db-> table ('product '). "where id = '$ ID'"); $ row = $ db-> fetch_array ($ sql0); if (! $ Row) {$ oldpx = 1;} else {$ oldpx = $ row ['sort '];} if ($ oldpx> 1) {$ db-> query ("update ". $ db-> table ('product '). "set sort = sort + 1 where sort = ". $ oldpx-1); $ db-> query ("update ". $ db-> table ('product '). "set sort = sort-1 where id = ". $ id);} header ("Location: product_list.php \ n"); exit;}/* Move Back */if ($ result = 'drop ') {$ sql1 = $ db-> query ("select sort from ". $ db-> table ('product '). "where id = '$ ID'"); $ row = $ db-> fetch_array ($ s Ql1); if (! $ Row) {$ oldpx = 9999;} else {$ oldpx = $ row ['sort '];} $ sql2 = $ db-> query ("select sort from ". $ db-> table ('product '). "order by sort desc limit 1"); $ rows = $ db-> fetch_array ($ sql2); if (! $ Rows) {$ maxpx = 9999;} else {$ maxpx = $ rows ['sort '];} if ($ oldpx <$ maxpx) {$ db-> query ("update ". $ db-> table ('product '). "set sort = sort-1 where sort = ". $ oldpx + 1); $ db-> query ("update ". $ db-> table ('product '). "set sort = sort + 1 where id = ". $ id);} header ("Location: product_list.php \ n"); exit ;}

In red, replace it with where id = '". $ id ."'");

If ($ _ REQUEST ["action"] = "up") {uppx ($ _ REQUEST ['goods _ id']);} elseif ($ _ REQUEST ["action"] = "down") {downpx ($ _ REQUEST ['goods _ id']);} function uppx ($ goods_id) {if (! $ Goods_id) {$ goods_id = 0;} $ SQL = $ GLOBALS ['DB']-> query ("select px from ". $ GLOBALS ['DB']-> table ('product '). "where id = ". $ goods_id); $ rs = $ GLOBALS ['DB']-> fetch_array ($ SQL); if (! $ Rs) {$ oldpx = 1;} else {$ oldpx = $ rs ['px '];} if ($ oldpx> 1) {$ oldpx = $ oldpx-1; $ GLOBALS ['DB']-> query ("update ". $ GLOBALS ['DB']-> table ('product '). "set px = px + 1 where px = ". $ oldpx); $ GLOBALS ['DB']-> query ("update ". $ GLOBALS ['DB']-> table ('product '). "set px = px-1 where id = ". $ goods_id);} header ("Location: product_list.php"); exit;} function downpx ($ goods_id) {if (! $ Goods_id) {$ goods_id = 0;} $ SQL = $ GLOBALS ['DB']-> query ("select px from ". $ GLOBALS ['DB']-> table ('product '). "where id = ". $ goods_id); $ rs = $ GLOBALS ['DB']-> fetch_array ($ SQL); if (! $ Rs) {$ oldpx = 1;} else {$ oldpx = $ rs ['px '];} // if $ oldpx = 1, $ sql1 = $ GLOBALS ['DB']-> query ("select * from ". $ GLOBALS ['DB']-> table ('product '). "order by px desc limit 1"); $ row = $ GLOBALS ['DB']-> fetch_array ($ sql1); if (! $ Row) {$ maxpx = 999;} else {$ maxpx = $ row ['px '];} // here the largest $ maxpx = 4 if ($ oldpx <$ maxpx) {$ oldpx = $ oldpx + 1; $ GLOBALS ['DB']-> query ("update ". $ GLOBALS ['DB']-> table ('product '). "set pixels = px-1 where px = ". $ oldpx); $ GLOBALS ['DB']-> query ("update ". $ GLOBALS ['DB']-> table ('product '). "set px = px + 1 where id = ". $ goods_id);} header ("Location: product_list.php"); exit ;}

Based on your code, I have demonstrated it completely to achieve the desired effect.