使用带有OUT参数的VB6调用MySQL存储过程

我在 MySQL(Server 5.5)中编写了这个程序

DELIMITER $$

DROP PROCEDURE IF EXISTS `InsertList` $$

CREATE DEFINER=`root`@`localhost` PROCEDURE `InsertList`(IN fName VARCHAR(20),IN fType VARCHAR(3),IN fFood varchar(20),Out fResult int)

BEGIN

  insert into tblguest (firstname,confirm,food) values (fName,fType,fFood);

  select count(id) from tblguest into fResult;

END $$

DELIMITER ;

当我从MysqL Query browser调用此过程时,它会按预期返回

Call InsertList ('V1','No','F1',@result);

Select @result;

– >它成功返回表中id的计数

我在VB6中编写了以下代码

Dim res As Integer
On Error GoTo chkErr

Set cmd = New ADODB.Command
cmd.ActiveConnection = cn
cmd.CommandType = adCmdstoredProc
cmd.CommandText = "InsertList"

cmd.Parameters.Append cmd.CreateParameter("fName",adVarChar,adParamInput,20,Text3.Text)
cmd.Parameters.Append cmd.CreateParameter("fType",3,Text2.Text)
cmd.Parameters.Append cmd.CreateParameter("fFood",Text1.Text)
cmd.Parameters.Append cmd.CreateParameter("fResult",adInteger,adParamOutput)

cmd.Execute

res = cmd("fResult")
MsgBox res
Exit Sub

chkErr:

    Select Case Err.Number
        Case Else
            Text4.Text = Err.Number & " - " & Err.Description
    End Select

但它尝试运行语句cmd.execute它会引发以下错误：

-2147467259 – [MysqL][ODBC 5.1 Driver][MysqLd-5.5.34]OUT or INOUT argument 4 for routine dbtest.InsertList is not a variable or NEW
pseudo-variable in BEFORE trigger

我见过用于sql的代码,那么MysqL本身是否存在使用带有OUT参数的存储过程的问题？

解决方法

这似乎是MysqL ODBC和C / API中未解决的错误

一种解决方案是使用带有准备变量的sql命令执行该操作：

Dim rs As ADODB.Recordset 

Set cmd = New ADODB.Command
cmd.ActiveConnection = cn
cmd.CommandType = adCmdText
cmd.CommandText = "call InsertList(?,?,@fResult)"

cmd.Parameters.Append cmd.CreateParameter("fName",Text1.Text)

cmd.Execute

'And after that,using the same connection,get the value of 
'@fResult from a single query:

Set rs = cn.Execute("select @fResult as fResult")
MsgBox rs!fResult

您将获得预期的价值.