不寻常的查询帮助请求 [英] Unusual Query Help Request

问题描述

我有一个查询，我试图使用php和mysql从3个不同的
表中提取数据。我原本希望有一个唯一的标识符

来帮助确保参照完整性，但似乎唯一的数字

不会总是有可能所以我不会银行在它上面。


我在这两个表''area''和''equipment''中有两个相似的字段和

虽然有一个在同一件事所称的两个区域内有两件不同的b / b $ b设备的可能性，如果我可以链接的话，有两件设备叫做同样的设备的可能性是多少？ br />
到那个''区域'列是不可能的，因此我唯一的身份


以下是我现有的代码看起来有效，但没有链接

'设备'列中表格的区域列。在几次输入数据库之前，没有注意到

问题。现在我可以看到我必须将各个表中的两列链接起来，以便为这三个表中的特定表行形成一个唯一的

标识符。


------------------------------------------

<？php

require_once（''generic_connect.php''）;

$ DBname =" Equipment";

$ area = $ _POST [''area''];


mysql_connect（$ DBhost，$ DBuser，$ DBpass）或死亡（无法连接到

主机$ DBhost"）;

mysql_select_db（$ DBname）或死（无法选择数据库$ DBname）;


$ query =" SELECT conveyors.equipname，conveyors.equipno，

conveyorors.mcc，conveyors.gb，conveyors.lube，conveyors.gbsize，

输送机.brgtype，conveyors.brgqty，motors.hp，motors.frame，

motors.amps，motors.rpm，equipcontacts.equipmanu，

equipcontacts.smodel，equipcontacts.sserial ，equipcontacts.vendphone

FROM输送机，电机，设备接触

WHERE conveyors.equipname = motors.equipname和

conveyors.equipname = equipcontacts.equipname" ;;

if（$ area！=" All"）$ query。=" and（conveyors.area =''$ area''或

motors.area =''$ area' '或equipcontacts.area =''$ area''）" ;;

$ result = mysql_query（$ query）;

--------- -------------------------


我希望链接每个表中的两列可能

简单如下：

WHERE conveyors.area.equipname = motors.area.equipname和

conveyors.area.equipname = equipcontacts。 area.equipname" ;;


但没有这样的运气。我的桌子是''传送带''，''马达''和

''equipcontacts''。


感谢任何回复。

cov

I have a query where I''m attempting to pull data from 3 different
tables using php and mysql. I had hoped to have a unique identifier
to help ensure referential integrity but it appears that unique number
won''t always be a possibility so I won''t bank on it at all.

I have two like fields in these two tables ''area'' and ''equipment'' and
though there is a possibility of having two different pieces of
equipment within two areas called by the same thing, the possibility
of having two pieces of equipment called the same thing if I can link
to that ''area'' column is impossible, hence my unique id

Below is what my existing code looks like that works but doesn''t link
the ''area'' column of a table to the ''equipment'' column. Didn''t notice
a problem until several entries to the db. Now I can see that I must
link the two columns within the individual tables to form a unique
identifier for those particular table rows within the three tables.

------------------------------------------
<?php
require_once(''generic_connect.php'');
$DBname = "Equipment";
$area = $_POST[''area''];

mysql_connect($DBhost, $DBuser, $DBpass) or die("Unable to connect to
host $DBhost");
mysql_select_db($DBname) or die("Unable to select database $DBname");

$query = "SELECT conveyors.equipname, conveyors.equipno,
conveyors.mcc, conveyors.gb, conveyors.lube, conveyors.gbsize,
conveyors.brgtype, conveyors.brgqty, motors.hp, motors.frame,
motors.amps, motors.rpm, equipcontacts.equipmanu,
equipcontacts.smodel, equipcontacts.sserial, equipcontacts.vendphone
FROM conveyors, motors, equipcontacts
WHERE conveyors.equipname = motors.equipname and
conveyors.equipname = equipcontacts.equipname ";
if ($area != "All") $query .= "and (conveyors.area=''$area'' or
motors.area=''$area'' or equipcontacts.area=''$area'')";
$result = mysql_query($query);
----------------------------------

I would have hoped that linking the two columns within each table may
be as simple as:
WHERE conveyors.area.equipname = motors.area.equipname and
conveyors.area.equipname = equipcontacts.area.equipname ";

but no such luck. My tables are ''conveyors'', ''motors'' and
''equipcontacts''.

thanks for any replies.
cov

推荐答案

DBname =" Equipment";

DBname = "Equipment";

area =

_POST [''area''];


mysql_connect（

_POST[''area''];

mysql_connect(

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