乘以2个不同表格的值

Question

我在PHP和SQL方面非常新颖，所以我正在对着墙壁敲打我的头，以了解如何让它达到我期待的结果。我正在研究产品库存网站。该网站允许您输入收到的订单/数量，并更新特定产品的总量。

有一个“交易”表;如接收更多产品和“产品”表格。

我试图用产品的单位价格乘以该产品的单位价格，以便它显示在该产品线上投入的总金额。

这里是我使用的代码 - 交易表是site_trans和产品的表格是site_products：

<form> 

<title>Products List</title> 
<border>true</border> 
<width>580</width> 

<fields> 
    <_count header="No" suffix="." width="25" align="center" /> 
    <product_name align="left" header="Name" /> 
    <product_number align="center" header="Number" /> 
    <product_count align="center" type="sql" header="Count"> 
     <sql> 
      <vars> 
       <table import="$this->tables[transactions]" type="eval" /> 
       <product import="product_id" type="field" /> 
      </vars> 

      <query>SELECT sum(trans_inventory) FROM {TABLE} WHERE trans_product='{PRODUCT}'</query> 
      <field>sum(trans_inventory)</field> 
     </sql> 

    </product_count> 
    <product_cost align="center" header="Cost" /> 
    <product_uom align="center" header="Unit" /> 
    <product_totcost align="center" type="sql" header="Total"> 
     <sql> 
      <vars> 
       <table import="$this->tables[transactions]" type="eval" /> 
       <prodcost import="product_cost" type="field" /> 
      </vars> 
      <query>SELECT sum(trans_inventory), sum('{PRODCOST}') FROM site_trans, site_products WHERE trans_product=product_id</query> 
      <field>sum(trans_inventory*product_cost)</field> 
     </sql> 
    </product_totcost> 

</fields> 

<header> 
    <titles>true</titles> 

    <buttons> 
     <export onclick="" button="export"> 
      <location>index.php?sub=export&action=products</location> 
     </export> 

     <add button="addnew">    
      <location>index.php?sub=products&action=add&returnurl={CURRENT_PAGE}</location> 
     </add> 
    </buttons> 
</header> 

<buttons> 

    <delete onclick="" button="delete" > 
     <location>javascript:if(confirm('Are you sure you want to delete this record ?')) window.location='index.php?sub=products&action=delete&product_id={PRODUCT_ID}&returnURL={CURRENT_PAGE}'</location> 
    </delete> 

    <details onclick="" button="details" > 
     <location>index.php?sub=products&action=details&section=1&product_id={PRODUCT_ID}&returnurl={CURRENT_PAGE}</location> 
    </details> 

</buttons> 

<items>25</items> 

那是给我的问题代码的特定部分是这样的：

 <product_totcost align="center" type="sql" header="Total"> 
     <sql> 
      <vars> 
       <table import="$this->tables[transactions]" type="eval" /> 
       <prodcost import="product_cost" type="field" /> 
      </vars> 
      <query>SELECT sum(trans_inventory), sum('{PRODCOST}') FROM site_trans, site_products WHERE trans_product=product_id</query> 
      <field>sum(trans_inventory*product_cost)</field> 
     </sql> 
    </product_totcost> 

请帮助！ :)

要添加到此;这里是事务代码（add.xml），用于更新site_trans数据库中每个产品的数量。也许这个代码将一些线索，我们错过了什么（我不知道）

<form> 
<title>{PRIVATE.FORM_ACTION_TITLE} Transaction</title> 
<action>index.php?sub=transactions&action=store</action> 
<name>edit</name> 
<width>580</width> 

<formtag>true</formtag> 
<border>true</border> 

<buttons>  
    <set> 
     <footer>true</footer> 
     <header>true</header> 
    </set> 

    <return onclick="" button="return"> 
     <location>{PRIVATE.FORM_PREVIOUS_PAGE}</location> 
    </return> 

    <save onclick="" button="saveall"> 
     <location>javascript:document.forms[0].submit();</location> 
    </save> 

</buttons> 

<redirect>index.php?sub=accounts</redirect> 

<fields> 
    <trans_id type="hidden" hidden="true"/> 
    <trans_date type="hidden" default="time()" action="eval"/> 
    <trans_user type="hidden" default="$_SESSION[minibase][raw][user_id]" action="eval"/> 
    <trans_post_ip type="hidden" default="$_SERVER[REMOTE_ADDR]" action="eval"/> 
    <trans_relation type="hidden" default="$_GET[trans_relation]" action="eval"/> 
    <trans_product type="hidden" default="$_GET[trans_relation]" action="eval"/> 

    <trans_inventory type="textbox" size="5" required="true" validate="A:2:200">    
     <title>Inventory</title>    
     <description>Box to either add (+40) or remove inventory (-40).</description> 
    </trans_inventory> 

    <trans_date2 type="date" now="true"> 
     <title>Date</title> 

     <fields> 
      <month format="int" default="now" /> 
      <day format="int" default="now" /> 
      <year from="2011" to="2110" default="now"/> 
     </fields> 
    </trans_date2> 


    <trans_description type="textarea" size="60:4">   
     <title>Description</title>   
    </trans_description> 

</fields> 

Answer 1

我不知道你用什么框架，但也许这样的事情...

<query>SELECT sum(trans_inventory*product_cost), sum('{PRODCOST}') FROM site_trans, site_products WHERE trans_product=product_id</query> 
<field>sum(trans_inventory*product_cost)</field> 

这只是一个猜测。

编辑：

<query>SELECT sum(st.trans_inventory*sp.product_cost) as total, sum('{PRODCOST}') FROM site_trans as st, site_products as sp WHERE st.trans_product=sp.product_id</query> 
<field>total</field> 

Answer 2

虽然你没有提到什么是你原来的问题的错误和问题的代码：

 <product_totcost align="center" type="sql" header="Total"> 
     <sql> 
      <vars> 
       <table import="$this->tables[transactions]" type="eval" /> 
       <prodcost import="product_cost" type="field" /> 
      </vars> 
      <query>SELECT sum(trans_inventory), sum('{PRODCOST}') FROM site_trans, site_products WHERE trans_product=product_id</query> 
      <field>sum(trans_inventory*product_cost)</field> 
     </sql> 
    </product_totcost> 

从你回答之前的响应，似乎你需要请确认您的字段名称，因此可能的解决方案可能是：

<query>SELECT sum(st.trans_inventory*sp.product_cost), sum('{PRODCOST}') FROM site_trans st, site_products sp WHERE st.trans_product=sp.product_id</query> 
<field>sum(st.trans_inventory*sp.product_cost)</field>