您如何将 output 参数从 vb.net 传递和接收到 mysql

Question

    Dim Def_Command_MySQL1 As MySql.Data.MySqlClient.MySqlCommand

    Def_Command_MySQL1.Parameters.Clear()
    Def_Command_MySQL1.CommandText = "SET @OutID = 10;"
    or
    Def_Command_MySQL1.CommandText = "UPDATE ID_Max1 SET IdMax = IdMax + 1 , @OutID = IdMax + 1 where TypeID>1"
    Def_Command_MySQL1.Parameters.Add(New SqlParameter("@OutID", SqlDbType.Int)).Value = 41
    Def_Command_MySQL1.Parameters("@OutID").Direction = ParameterDirection.Output
    Def_Command_MySQL1.ExecuteNonQuery()
    IDMax_Update = Def_Command_MySQL1.Parameters("@OutID").Value   

Err.Description "You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '41 = 10' at line 1" String

or

Error = You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '1=IdMax + 1 where TypeID>1' at line 1

Answer 1

First you set AllowUserVariables on True(Default is False in your connection string see https://dev.mysql.com/doc/connector-net/en/connector-net-6-10-connection-options.html

second get rid of the parameter code, because you replace mysql user defined variables @OutID with an actual value , which results in your error message.

With

SET @OutID = 10;"

You set in mysql a user defined variable @OutID to the numer 10.

But in general, following code add two parameters to a insert query

 Def_Command_MySQL1.CommandText = "INSERT INTO myTable (myColumn1, myColumn2) VALUES (@C1, @C2)"
 Def_Command_MySQL1.Parameters.AddWithValue("@C1", 1)
 Def_Command_MySQL1.Parameters.AddWithValue("@C2", 2)
 Def_Command_MySQL1.ExecuteNonQuery()