如何从3个表中获取数据? [英] how to fetch data from 3 tables ?
问题描述
我不知道子查询或从类别和子类别加入和获取记录以及应用程序名称3表格和表格结构是
类别
CAT_ID
CAT_NAME
CAT_IS_ACTIVE
子类别
SCAT_ID
SCAT_NAME
SCAT_CAT_ID
SCAT_IS_ACTIVE
AppStatus
STS_ID
STS_NAME
STS_IS_ACTIVE
我发现此记录
类别ID
类别名称
子类别名称
状态
创建
修改
特色
- 谢谢
i dont know sub query or join and fetch record from the category and subcategory and also app name 3 tables and the table stucture is
Category
CAT_ID
CAT_NAME
CAT_IS_ACTIVE
SubCategory
SCAT_ID
SCAT_NAME
SCAT_CAT_ID
SCAT_IS_ACTIVE
AppStatus
STS_ID
STS_NAME
STS_IS_ACTIVE
and am find out this records
category id
category name
sub category name
status
created
modified
featured
--thanks
推荐答案
有些是显而易见的:
Some of it is obvious:
SELECT c.CAT_ID, c.CAT_NAME, s.SCAT_NAME
FROM Category c
JOIN SubCategory s
ON c.CAT_ID=s.SCAT_CAT_ID
但其余字段为status,created,modified,和特色我无法帮助,因为我不知道你从哪里得到这些信息。另外,我看不到任何将你的AppStatus表加入到其他两个中的信息,所以我无法帮助你提供任何信息!
but the remaining fields "status", "created", "modified", and "featured" I can't help with as I have no idea where you get that information from. In addition, I can't see any information joining your AppStatus table to the other two, so I can't help you with any information from that!
首先从Category表中获取所有信息。
然后使用类别主键从SubCategory表搜索Sub Category。
你的表应该是这样的。
类别ID - 类别名称
1 - 子类别ID - 子类别名称 - 子类别状态
2 - 子类别ID - 子类别名称 - 子类别状态
AppStatus做什么?
First get all from Category table.
Then search Sub Category from SubCategory table using the category primary key.
Your table should be like this.
category id - category name
1 - Subcategory id - Subcategory name - Subcategory Status
2 - Subcategory id - Subcategory name - Subcategory Status
What does AppStatus do??
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