Question

我尝试了很多不同的东西，但此时我很难过。

Public Function GetCust(email As String) As Integer
    Dim cs As String = <connection string>
    Dim conn As New MySqlConnection(cs)
    Dim custId As Integer
    Dim cust_query As String = "SELECT entity_id FROM customer_entity WHERE email = '@email'"
    Dim com As New MySqlCommand(cust_query, conn)
    Dim reader As MySqlDataReader

    Try
        conn.Open()
        com.Parameters.Add("@email", MySqlDbType.String)
        com.Parameters("@email").Value = email
        reader = com.ExecuteReader
        While reader.Read()
            custId = reader.GetInt16(0)
        End While
        MsgBox(custId)
    Catch ex As Exception
        MsgBox(ex.ToString)
    End Try

    Return custId
End Function

它应该只从表中拉出一列和一行，所以我只应该从查询中获得一个值，但它不会进入循环。看起来像我的语法错误，但似乎无法找到它。提前谢谢！

Answer 1

您应该删除SQL字符串中的email参数周围的引号：

Dim cust_query As String = "SELECT entity_id FROM customer_entity WHERE email = @email"

这将生成类似于

的SQL

WHERE email = ''myemail@mydomain.com''

什么时候应该

WHERE email = 'myemail@mydomain.com'

MySQL数据读取器没有进入循环

1 个答案: