加入多表vb.net [英] join multi tabels vb.net

问题描述

嗨


我有很多表格我想加入他们填写网格视图：



OperatingAreas：OANo， OAName

分区：subarea_id，name.OAName

变电站：substation_id，name，subarea_id

Equipments_Class：equipment_class_id，name

Equipmen_Name：equipment_name_id，name，equipment_class_id，substation_id



我有gridview显示Area，Subaarea，Substation，EqipClass&的名称。 EquipName

（取决于平均多对1）

分区依赖于OperatingAreas

变电站取决于分区

Equipment_Name取决于变电站& Equipment_Class



我在vb.net中的查询：

Hi
I have many tabels I want to join them to fill a gridview:

OperatingAreas: OANo,OAName
Subarea:subarea_id,name.OAName
Substation:substation_id,name,subarea_id
Equipments_Class:equipment_class_id,name
Equipmen_Name:equipment_name_id,name,equipment_class_id,substation_id

I have gridview display the names of Area,Subaarea,Substation,EqipClass & EquipName
(depends on mean many to 1)
Subarea depends on OperatingAreas
Substation depends on Subarea
Equipment_Name depends on Substation & Equipment_Class

My query in vb.net:

"select a.OAName as Area, s.Name as Subarea, ss.Name as Substation, eqc.Name as Equipment_Class, eqn.Equipment_Name_id, eqn.Name as Equipment_Name from Equipments_Names as eqn, " _
& " OperatingAreas as a INNER JOIN Subarea as s on a.OANo = s.OANo INNER JOIN Substations as ss on ss.Subarea_id = s.Subarea_id " _
& " INNER JOIN Equipments_Class as eqc on eqc.Equipment_Class_id = eqn.Equipment_Class_id"

查询不起作用，因为表名Equipments_Names表我不知道如何以正确的方式实现查询



我的frind告诉use使用2个查询一个用于Equipments_Class with Equipments_Name，第二个用于Substations with Equipments_Names在griddiw中的rowdatabound（作为2个数据表）



但是我希望在1个查询中或者在其他单词中使用一个数据表，例如在一个查询中加入2个查询。



任何帮助？

谢谢

the query not works because table name Equipments_Names table I don`t knowhow to implement the query at correct way

My frind told use use 2 queries one for Equipments_Class with Equipments_Name and the second one for Substations with Equipments_Names in a rowdatabound in gridveiw (as 2 datatables)

but I want make them in 1 query or in other word one datatable like join 2 queries in one query.

Any help?
Thank you

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