使用选择语句的SQL连接查询

本文介绍了使用选择语句的SQL连接查询的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有一个oc_category_description表，其中各列是:

I have one table of oc_category_description where columns are :

• category_id
• 名称

和其他表oc_category，其中列为:

and other table oc_category where columns are :

• category_id
• 图片
• parent_id

这是oc_category_description表的示例图片

Here the sample pic of oc_category_description table

oc_category表

oc_category table

在这里我要显示名称，category_id，图像，parent_id，其中oc_category parent_id为0;

Here i am want to show name, category_id, image, parent_id where oc_category parent_id is 0;

这是sql:

php

function getMainCategory() { $stmt = $this->con->prepare("SELECT category_id, image, parent_id, (SELECT oc_category_description.name FROM oc_category_description WHERE oc_category.category_id = oc_category_description.category_id) FROM oc_category WHERE parent_id = 0 ORDER BY category_id ASC"); $stmt->execute(); $stmt->bind_result($category_id, $image, $parent_id, $name); $users = array(); while ($stmt->fetch()) { $temp = array(); $temp['category_id'] = $category_id; $temp['image'] = $image; $temp['parent_id'] = $parent_id; $temp['name'] = $name; array_push($users, $temp); } return $users; }

但是它什么也没返回:(

but it returns nothing :(

推荐答案

在以下脚本中尝试此操作-

Try this below script-

SELECT oc_category.category_id, oc_category.image, oc_category.parent_id, oc_category_description.name FROM oc_category INNER JOIN oc_category_description ON oc_category.category_id = oc_category_description.category_id WHERE oc_category.parent_id = 0 ORDER BY oc_category.category_id ASC