欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页  >  后端开发

求查询优化方法

程序员文章站 2022-06-10 19:38:03
...
请问下面的代码有优化的方法吗

$catalog_1 = "select name from commodity where catalog = 1 ORDER BY rank desc LIMIT 10";$result_1 = mysql_query($catalog_1);while($row_1 = mysql_fetch_assoc($result_1)){     $response [] = $row_1;}$catalog_2 = "select name from commodity where catalog = 2 ORDER BY rank desc LIMIT 10";$result_2 = mysql_query($catalog_2);while($row_2 = mysql_fetch_assoc($result_2)){     $response [] = $row_2;}$catalog_3 = "select name from commodity where catalog = 3 ORDER BY rank desc LIMIT 10";$result_3 = mysql_query($catalog_3);while($row_3 = mysql_fetch_assoc($result_3)){     $response [] = $row_3;}$catalog_4 = "select name from commodity where catalog = 4 ORDER BY rank desc LIMIT 10";$result_4 = mysql_query($catalog_4);while($row_4 = mysql_fetch_assoc($result_4)){     $response [] = $row_4;}$catalog_5 = "select name from commodity where catalog = 5 ORDER BY rank desc LIMIT 10";$result_5 = mysql_query($catalog_5);while($row_5 = mysql_fetch_assoc($result_5)){     $response [] = $row_5;}$catalog_6 = "select name from commodity where catalog = 6 ORDER BY rank desc LIMIT 10";$result_6 = mysql_query($catalog_6);while($row_6 = mysql_fetch_assoc($result_6)){     $response [] = $row_6;}$catalog_7 = "select name from commodity where catalog = 7 ORDER BY rank desc LIMIT 10";$result_7 = mysql_query($catalog_7);while($row_7 = mysql_fetch_assoc($result_7)){     $response [] = $row_7;}$catalog_8 = "select name from commodity where catalog = 8 ORDER BY rank desc LIMIT 10";$result_8 = mysql_query($catalog_8);while($row_8 = mysql_fetch_assoc($result_8)){     $response [] = $row_8;}$catalog_11 = "select name from commodity where catalog = 11 ORDER BY rank desc LIMIT 10";$result_11 = mysql_query($catalog_11);while($row_11 = mysql_fetch_assoc($result_11)){     $response [] = $row_11;}$catalog_10 = "select name from commodity where catalog = 10 ORDER BY rank desc LIMIT 10";$result_10 = mysql_query($catalog_10);while($row_10 = mysql_fetch_assoc($result_10)){     $response [] = $row_10;}


回复讨论(解决方案)

function getCataLog($catalog){	$catalog = "select name from commodity where catalog = ".$catalog." ORDER BY rank desc LIMIT 10";	$result = mysql_query($catalog); 	while($row = mysql_fetch_assoc($result)){	     $response [] = $row;	}}

改写成方法

是这样调用吗 getCataLog(11);

但没数据出来

是这样调用吗 getCataLog(11);

但没数据出来

function getCataLog($catalog){    $catalog = "select name from commodity where catalog = ".$catalog." ORDER BY rank desc LIMIT 10";    $result = mysql_query($catalog);      while($row = mysql_fetch_assoc($result)){         $response [] = $row;    }    return $response;}

还有个神奇的问题

catalog = 11 数据库有3条记录
catalog = 12 数据库有11条记录

$responses = getCataLog(11) + getCataLog(12);

这样输出应该是有14条记录的,但实标只输出了10条。而且catalog = 12的数据是从第四条开始接的

不是这么用的 php里面的 + 相比于数组的合并 array_merge 相同键值的被覆盖掉了

select name,catalog,rank from commodity c where 10 > (select count(*) from commodity where catalog=c.catalog and id>c.id) and catalog in (1,2,3,4,5,6,7,8,10,11) order by c.catalog,c.rank desc

function getCataLog($catalog,&$response = array()){    $catalog = "select name from commodity where catalog = ".$catalog." ORDER BY rank desc LIMIT 10";    $result = mysql_query($catalog);      while($row = mysql_fetch_assoc($result)){         $response [] = $row;    }}$response = array();getCataLog(1,$response);var_dump($response);getCataLog(2,$response);var_dump($response);

select name,catalog,rank from commodity c where 10 > (select count(*) from commodity where catalog=c.catalog and id>c.id) and catalog in (1,2,3,4,5,6,7,8,10,11) order by c.catalog,c.rank desc


请问再加两个条件怎么加啊,我这样加了,但这样加了和数据库对不上,少了很多条数据。

$marketId = $_GET['marketId'];$cityId = $_GET['cityId'];"select name from commodity where catalog = 1 and cityId = $cityId and marketId = $marketId ORDER BY rank desc LIMIT 10""select name,catalog,rank from commodity c where 10 > (select count(*) from commodity where catalog=c.catalog and id>c.id) and catalog in (1,2,3,4,5,6,7,8,10,11) and cityId = $cityId and marketId = $marketId order by c.catalog,c.rank desc"
相关标签: 求查询优化方法