如何避免使用这个嵌套的 while 循环和其中的 SQL 查询执行？

Question

我必须从这些表中检索某些数据，我认为这些数据是正确的（我认为），但是我实现它的方法非常慢并且可能编程错误，我这样做只是为了我，所以看起来很漂亮代码不是优先级，但它必须在“正常”时间运行，不像现在它在 10-15 秒内运行 ~ 。

这是我的代码：

$arr1=[];

$sqlquery="Select codart,canped,codpro 
           from gcpedl 
           where gcpedl.numped in (
                                   select numped 
                                   from gcpedc 
                                   where texto like '".$_POST['codobra']."'
                                   )";
$query_execute = mssql_query($sqlquery);

while($query_result=mssql_fetch_array($query_execute)){
    $arr1=$query_result;
    $sqlq="Select distinct alart.codart,pultcomp,alart.codpro 
           from alart,gcpedl 
           where gcpedl.numped in 
                 ( select numped 
                   from gcpedc 
                   where texto like '".$_POST['codobra']."') 
                     and alart.codart in 
                        (Select codart 
                         from gcpedl 
                         where numped in 
                             ( select numped 
                               from gcpedc 
                               where texto like '".$_POST['codobra']."')) ";
    $sqlex =mssql_query($sqlq);

    while($sqlre=mssql_fetch_array($sqlex)){
        if (    trim(strtoUPPER($sqlre['codart'])," ")==trim(strtoUPPER($query_result['codart'])," ") 
            and $sqlre['codpro']==$query_result['codpro'] )
        {
            if (    $arr1['codart'] != 'CUADRO' 
                and $arr1['codart'] != 'cuadro' 
                and $arr1['codart'] != 'instalacion' 
                and $arr1['codart'] != 'INSTALACION')
            {
                $materiales= $materiales+ ($sqlre['pultcomp']*$arr1['canped']);
            }
        }
    }

编辑：这段代码的目的是遍历每一篇文章（codart），并获取它的数量（canped）和它的提供者（codpro），然后循环遍历另一个表中的每一篇文章，并匹配 codart 和供应商，并取出价格（pultcomp）乘以数量。

Edit2：要从第一个表（gcpedl）和第二个表（alart）中选择文章，我必须使用第三个表（gcpedc）和 where 子句对它们进行子选择（或加入）。

Edit3：仅使用一个查询无法使其工作，我走得更远是这样的：

$arr1=[];

$sqlquery="Select  g1.codart,
                g1.canped,
                g1.codpro 
        from gcpedl as g1
        inner join gcpedc as g2
            ON g1.numped = g2.numped
        where g2.texto like '".$_POST['codobra']."'";
  $query_execute = mssql_query($sqlquery);

while($query_result=mssql_fetch_array($query_execute)){
    $arr1=$query_result;
        $sqlq="Select distinct  a.codart,
                    a.pultcomp,
                    a.codpro 
    from alart AS a
    inner join gcpedl AS g
        on a.codart = g.codart 
    inner join gcpedc g1
        on g.numped = g1.numped 
    where g.numped in (select numped from gcpedc where texto like '".$_POST['codobra']."') ";
    $sqlex =mssql_query($sqlq);

    while($sqlre=mssql_fetch_array($sqlex)){if (trim(strtoUPPER($sqlre['codart'])," ")==trim(strtoUPPER($query_result['codart'])," ") and $sqlre['codpro']==$query_result['codpro'] ){
        if ($arr1['codart'] != 'CUADRO' and $arr1['codart'] != 'cuadro' and $arr1['codart'] != 'instalacion' and $arr1['codart'] != 'INSTALACION'){
$materiales= $materiales+ ($sqlre['pultcomp']*$arr1['canped']);}

我终于解决了，只是我太睡了，查询可以转换为只有1个查询，执行时间大大减少。

Select gcpedl.codart, (gcpedl.canped*alart.pultcomp) as precio, alart.codpro from alart,gcpedl where gcpedl.numped in (Select numped from gcpedc where texto like '".$_POST['codobra']."') and alart.codart=gcpedl.codart and alart.codpro=gcpedl.codpro 

Answer 1

您可以使用正确的 JOIN 语句来避免它们。

$sqlq="Select distinct  a.codart,
                        g.pultcomp,
                        g1.canped,
                        a.codpro 
        from alart a
        inner join gcpedl g
            on a.codart = g.codart 
        inner join gcpedc g1
            on g.numped = g1.numped 
        where g.texto like '".$_POST['codobra']."' and g1.texto like '".$_POST['codobra']."' ";

试一试。