Sql Oracle vb.net选择参数dbnull.value
这项工作:Sql Oracle vb.net选择参数dbnull.value,sql,vb.net,oracle,Sql,Vb.net,Oracle,这项工作: Dim stSQL as String = "Select ID From Table Where COL Is Null" Dim cmd As New OracleCommand cmd.Connection = ... cmd.CommandText = stSQL cmd.BindByName = True Try Dim oRet As Object = cmd.ExecuteScalar If oRet IsNot N
Dim stSQL as String = "Select ID From Table Where COL Is Null"
Dim cmd As New OracleCommand
cmd.Connection = ...
cmd.CommandText = stSQL
cmd.BindByName = True
Try
Dim oRet As Object = cmd.ExecuteScalar
If oRet IsNot Nothing Then
If oRet > 0 Then
...
End If
End If
Catch ex As Exception
Throw ex
End Try
如果我将sql字符串更改为使用参数:
Dim stSQL as String = "Select ID From Table Where COL = :COL"
and add:
cmd.Parameters.Add(New OracleParameter("COL", DBNull.Value))
它不起作用。。。(oRet=没什么)有什么想法吗-谢谢
Oracle 12c,VS2017,Oracle.DataAccess v4.112.3.0NULL
表示“未定义”,您无法对相同的数据进行比较。通过=NULL
进行比较的任何内容都返回false
必须使用,其中COL为NULL
NULL
表示“未定义”,不能对相等值进行比较。通过=NULL
进行比较的任何内容都返回false
必须使用列为NULL的