查询和表达式 vb net 中缺少运算符

Question

Dim da As OleDbDataAdapter = New OleDbDataAdapter("Select sum[Shark Individual Weight] from FishCaught'", myConnection)
Dim ds As DataTable = New DataTable()
da.Fill(ds)
DataGridView1.DataSource = ds

myConnection.Close()

你好。我正在使用 vb.net 连接到 ms 访问。我不断收到错误“查询表达式中缺少运算符”。我想知道我的sql语句有什么问题。

    Dim da As OleDbDataAdapter = New OleDbDataAdapter("Select Sum([Shark Individual Weight]) From FishCaught Where ([OperationID]) = '" & TextBoxOpID4.Text & "'", myConnection)
    Dim ds As DataTable = New DataTable()
    da.Fill(ds)
    DataGridView2.DataSource = ds

我认为我的 SQL 语法是错误的。实际应该怎么写？我收到此错误“条件表达式中的数据类型不匹配”。如果我只是写' Dim da As OleDbDataAdapter = New OleDbDataAdapter("Select Sum([Shark Individual Weight]) From FishCaught'，总和将被显示。所以我认为 WHERE 子句中有错误。任何帮助将不胜感激，谢谢.

Answer 1

Sum 是一个函数，而您有一个令人不安的单引号，因此：

"Select Sum([Shark Individual Weight]) From FishCaught"

Answer 2

这是你的代码

Dim da As OleDbDataAdapter = New OleDbDataAdapter("Select sum[Shark Individual Weight] from FishCaught'", myConnection)
Dim ds As DataTable = New DataTable()
da.Fill(ds)
DataGridView1.DataSource = ds

myConnection.Close()

应该是代码一定是这样的

Dim da As OleDbDataAdapter = New OleDbDataAdapter("Select sum(The_Name_Of_The_Field) from FishCaught'", myConnection)
Dim ds As DataTable = New DataTable()
da.Fill(ds)
DataGridView1.DataSource = ds

myConnection.Close()

是这样吗，试试这个FINAL

 Dim da As OleDbDataAdapter = New OleDbDataAdapter("Select sum(Shark__Individual_Weight) as FishWeight from FishCaught'", myConnection)
    Dim ds As DataTable = New DataTable()
    da.Fill(ds)
    DataGridView1.DataSource = ds

    myConnection.Close()

尝试将Shark Individual Weight 更改为Shark_Individual_Weight 会起作用

Answer 3

"Select Sum([field name]) From FishCaught" 应该可以工作。您是否检查过数据库中的字段名称，它不应包含任何空格。为了使字段名称更具可读性，您可以将任何空格替换为“_”。