如何在 C# 中显示 MySQL “PRINT” 命令的输出？

Question

我正在尝试使用 c# asp net 运行 mysql 存储过程。

在 mysql 中尝试过的这个存储过程工作正常。

而是在我的项目后面的代码上进行测试，我有 mysql 语法错误。

ERROR [42000] [MySQL][ODBC 5.1 Driver][mysqld-8.0.12]You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'mysp' at line 1

如何提取“PRINT”命令的输出，即 C# 中的过程，我该怎么做？

.cs

using (OdbcConnection cn =
  new OdbcConnection(ConfigurationManager.ConnectionStrings["cn"].ConnectionString))
{
    using (OdbcCommand command =
        new OdbcCommand("mysp", cn))
    {
        try
        {
            command.Connection.Open();
            command.CommandType = CommandType.StoredProcedure;
            command.Parameters.AddWithValue("sYear", ddlyear.SelectedValue);

            using (OdbcDataAdapter sda = new OdbcDataAdapter(command))
            {
                DataTable dt = new DataTable();
                sda.Fill(dt);
                gv.DataSource = dt;
                gv.DataBind();
            }
        }
        catch (Exception ex)
        {
            throw new ApplicationException("operation failed!", ex);
        }
        finally
        {
            command.Connection.Close();
        }
    }
}

sp

CREATE DEFINER=`root`@`%` PROCEDURE `mysp`(IN sYear VARCHAR(255))
BEGIN

DECLARE 2sYear VARCHAR(255);
SET 2sYear = sYear;

SET @s = CONCAT('SELECT * FROM `mytable_',2sYear,'`;');
PREPARE stmt FROM @s;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

END

编辑

这个问题在nbk用户的建议下解决了，原文有复制粘贴错误谢谢

Answer 1

你的程序变量是 sYear

但是在你的代码中你使用了sAnno

CREATE TABLE mytable_2025 ( id int)

✓

CREATE  PROCEDURE `mysp`(IN sYear VARCHAR(255))
BEGIN

DECLARE 2sYear VARCHAR(255);
SET 2sYear = sYear;

SET @s = CONCAT('SELECT * FROM `mytable_',2sYear,'`;');
PREPARE stmt FROM @s;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

END

✓

call mysp('2025')

| id |
| -: |

✓

SELECT @s

| @s                            |
| :---------------------------- |
| SELECT * FROM `mytable_2025`; |

SELECT @2sYear

| @2sYear |
| :------ |
| null    |

db<>fiddle here

如何在 C# 中显示 MySQL “PRINT” 命令的输出？

How Can i display the output of MySQL “PRINT” Command in C#?

c#

mysql

asp.net

stored-procedures