MySQL 数据读取器未进入循环 [英] MySQL Data Reader not entering the loop
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问题描述
我尝试了很多不同的方法,但此时我被难住了.
I have tried many different things but at this point I am stumped.
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
它应该只从表中提取一列和一行,所以我应该只从查询中提取一个值,但它没有进入循环.似乎它是我的语法错误,但似乎无法找到它.提前致谢!
It should be pulling only one column and one row from a table so i should only have one value out of the query but it isn't entering the loop. Seems like its a syntax error on my part but can't seem to find it. Thanks in advance!
推荐答案
您应该删除 SQL 字符串中电子邮件参数周围的引号:
You should remove the quotes around the email parameter in the SQL string:
Dim cust_query As String = "SELECT entity_id FROM customer_entity WHERE email = @email"
这将生成看起来像
WHERE email = ''myemail@mydomain.com''
什么时候该
WHERE email = 'myemail@mydomain.com'
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