SQL执行后索引超出范围 [英] Index out of range after SQL execution

问题描述

我有一个用VB编写的内联查询SELECT语句。当我尝试运行它时，它会提示我一个错误消息IndexOutOfRangeException。我尝试调试它，并在ExecuteReader（）之后找到错误提示。

起初我认为这是由于我的返回值为NULL但是在我的代码中添加了IsDBNull之后错误仍然存​​在。

以下是我的代码：

Hi, I have a inline query SELECT statement written in VB. When I try to run it, it prompt me an error message IndexOutOfRangeException. I tried to debug it and found the error prompt after ExecuteReader().
At first I thought it was due to my returned value is NULL but the error still persist after I have added IsDBNull in my codes.
Below are my codes:

Try
    cnSql = New SqlConnection(SQL_CONNECTION_STRING)
    cnSql.Open()

    strSQL = "SELECT ISNULL(MIN(SH.shipping_start_date), GETDATE()) AS StartDate "
    strSQL = strSQL + "FROM Shipping AS SH INNER JOIN Working AS WK ON SH.shipping_id = WK.shipping_id "
    strSQL = strSQL + "WHERE WK.woNo = '" + number + "'"

    cmSql = New SqlCommand(strSQL, cnSql)
    readerSQL = cmSql.ExecuteReader()

    If readerSQL.Read() Then
        If Not IsDBNull(readerSQL.Item("shipping_start_date")) Then
            woStartDate = readerSQL.Item("shipping_start_date")
        End If
    Else
        ShipStartDate = DateTime.Now
    End If


    readerSQL.Close()
    cnSql.Close()
    cmSql.Dispose()
    cnSql.Dispose()

Catch ex As SqlException
    MsgBox(ex.Message, MsgBoxStyle.Critical, "SQL Error!")

Catch ex As Exception
    MsgBox(ex.Message, MsgBoxStyle.Critical, "General Error!")'error happen here

我尝试过： < br $>


1.在我的代码中添加了IsDBNull来过滤掉从DB返回的NULL值。

2.试图直接在SQL Server中执行查询没有任何错误。

What I have tried:

1. Added IsDBNull in my codes to filter out NULL value returned from DB.
2. Tried to excute the query directly in SQL Server without any error.

推荐答案

我不是SQL专家，但看起来返回的列名为 StartDate 并在代码中检查 shipping_start_date 。

I am not SQL expert, but it looks like the returned column is named StartDate and you check shipping_start_date in your code.

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