Question

如果我删除第二个连接查询，它的工作原理，但不起作用！

错误：列参考＆＃34;类别＆＃34;模棱两可的第1行：...＆＃34;，＆＃34; prefix_product＆＃34;＆＃34; full_desc＆＃34; as＆＃34; description＆＃34;，＆＃34; category＆＃34; ... ^

SELECT "prefix_product"."id" as "product_id", 
       "prefix_product"."title" as "name", 
       "prefix_product"."short_desc" as "briefDescription",
       "prefix_product"."full_desc" as "description", 
       "category" as "productCategory" 
FROM "prefix_product" 
JOIN "prefix_category" 
   ON "prefix_product"."category"="prefix_category"."id" 
JOIN "prefix_category_attribs" 
   ON "prefix_product"."category"="prefix_category"."parent" 
WHERE "vendor" = '8'

我使用codeigniter3和postgresql，在codeigniter中，我有：

    $this->db->select(['prefix_product.id as product_id', 'prefix_product.title as name', 'prefix_product.short_desc as briefDescription', 'prefix_product.full_desc as description','category as productCategory']);
$this->db->where('vendor',$vendorId);
$this->db->from($this->tblName);
$this->db->join('prefix_category','prefix_product.category=prefix_category.id');
$this->db->join('prefix_category_attribs','prefix_product.category=prefix_category.parent');
$queryResult =$this->db->get()->result();

感谢

Answer 1

似乎有多个表具有相同的列名，即category。因此，您需要在category子句中为列SELECT添加前缀，以便明确指定列所属的表：

"prefix_product"."category" as "productCategory"

在多个连接postgresql中，列是不明确的

1 个答案: