sql查询如何把2“where”条件

Question

首先这是表关系。 以下是我想要实现的目标

Dim ad As New SqlDataAdapter("SELECT inventory.ItemName,record_item.Amount FROM record_item,inventory WHERE (record_item.RecordID = '" & listbox1.SelectedItem & "')", conn)

如果我试图根据我拥有的RecordID获取ItemName，我是否需要放2条件？如果我这样做，怎么样？

WHERE (record_item.RecordID = '" & listbox1.SelectedItem & "')和WHERE(record_item.ItemID=inventory.ItemID)

Answer 1

WHERE (something) AND (something else)

Answer 2

只是这样做：

SELECT inventory.ItemName,record_item.Amount FROM record_item,inventory
WHERE record_item.RecordID = '" & listbox1.SelectedItem & "' and record_item.ItemID=inventory.ItemID

Answer 3

没有第二个WHERE子句

WHERE 
    (record_item.RecordID = '" & listbox1.SelectedItem & "') 
and (record_item.ItemID=inventory.ItemID)

Answer 4

而不是像你这样使用两个条件

WHERE（第一条件）AND（第二条件）。

Answer 5

  

Dim ad As New SqlDataAdapter（“SELECT inventory.ItemName，record_item.Amount   FROM record_item，inventory WHERE record_item.RecordID ='“＆amp; listbox1.SelectedItem＆amp;”'AND record_item.ItemID = inventory.ItemID“，conn）

Answer 6

检查以下代码......

Dim ad As New SqlDataAdapter("SELECT inventory.ItemName, record_item.Amount FROM record_item, inventory WHERE (record_item.RecordID = '" & listbox1.SelectedItem & "' AND record_item.ItemID=inventory.ItemID)", conn)

如果您的record_item.RecordID是整数，那么下面的查询就可以了......

Dim ad As New SqlDataAdapter("SELECT inventory.ItemName, record_item.Amount FROM record_item, inventory WHERE (record_item.RecordID = " & listbox1.SelectedItem & " AND record_item.ItemID=inventory.ItemID)", conn)

Answer 7

在简单的SELECT查询中不能使用多个WHERE，您可以使用SUBQUERY或其他。

在您的情况下，为什么您没有实施建议的答案。 你也可以使用IN子句，

WHERE (record_item.RecordID IN ('" & listbox1.SelectedItem & "', inventory.ItemID )