从表JOIN中获取两个字段的值

I have a mysql table called districts where all the districts and their id's are stored. I have another table called tbl_units where unit details such as office_address, office_district, factory_address, factory_district are saved.

我有一个名为区的mysql表,其中存储了所有区域及其ID。我有另一个名为tbl_units的表,其中保存了office_address,office_district,factory_address,factory_district等单元详细信息。

Now if want to get the names of the districts from their id's by JOIN ing the two tables, how should I write the query ? Because

现在,如果想通过加入两个表来从他们的id获取区域的名称,我应该如何编写查询?因为

SELECT u.*, d.district_name
FROM  tbl_unit_details as u,
    tbl_districts as d 
WHERE u.unit_id = '$unit_id' 
    AND u.district_id = d.district_id 
    AND u.factory_district_id = d.district_id 
ORDER BY unit_name

returns only the first , i.e. district name of office.

只返回第一个,即地区的办公室名称。

2 个解决方案

#1

Join the districts table to the units table twice; once for each district type. Use aliases to distinguish each instance of the district table. If you like, you can include the optional AS keyword.

将区域表加入单位表两次;每个地区类型一次。使用别名来区分分区表的每个实例。如果您愿意,可以包含可选的AS关键字。

#2

try this out maybe it can help

试试这个也许它可以帮助

$sql=mysql_query("SELECT u.*,t.* FROM districts as u,tbl_units as t WHERE u.id=t.id");
$row=mysql_fetch_array($sql);
//echo your required result however you want

here u.id represents districs table id and t.id represents tbl_units table id, but in this case your id for tbl_units must be a foreign key.

这里u.id表示districs表id,t.id表示tbl_units表id,但在这种情况下,tbl_units的id必须是外键。

#1