Question

我尝试通过我的应用程序（C＃winapp）执行此命令，但它显示错误，如参数＆＃39; @sqlstmt＆＃39;必须定义，但我尝试这个命令由navicat它运作良好，请帮助我

"DELIMITER $$" +

                " DROP PROCEDURE IF EXISTS " + txtDB.Text + ".`index_startTime` $$" +
                " CREATE PROCEDURE " + txtDB.Text + ".`index_startTime`" +
                " (" +
                    " given_database VARCHAR(64)," +
                    " given_table    VARCHAR(64)," +
                    " given_index    VARCHAR(64)," +
                    " given_columns  VARCHAR(64)" +
                " )" +
                " BEGIN" +

                    " DECLARE IndexIsThere INTEGER;" +

                    " SELECT COUNT(1) INTO IndexIsThere" +
                    " FROM INFORMATION_SCHEMA.STATISTICS" +
                    " WHERE table_schema = given_database" +
                    " AND   table_name   = given_table" +
                    " AND   index_name   = given_index;" +

                    " IF IndexIsThere = 0 THEN" +
                        " SET @sqlstmt = CONCAT('CREATE INDEX ',given_index,' ON '," +
                        " given_database,'.',given_table,' (',given_columns,')');" +
                        " PREPARE st FROM @sqlstmt;" +
                        " EXECUTE st;" +
                        " DEALLOCATE PREPARE st;"+
                    " ELSE" +
                        " SELECT CONCAT('Index ',given_index,' already exists on Table ',"+
                        " given_database,'.',given_table) CreateindexErrorMessage; "+
                    " END IF;"+

                " END $$" +

                " DELIMITER ;";

Answer 1

该场景是需要调整mysql连接以允许用户变量支持的场景。如

string connString = @"server=localhost;userid=myUser;password=thePassword;database=stackoverflow;Allow User Variables=True";

（注意上面的结尾）。请参阅有关Allow User Variables=True的MySQL手册页here。如果你不这样做，那么它会在用@标志上用变量部分中的字符串输入。{/ p>

测试：

public void testCreateFunctionOnDB()
{   // http://stackoverflow.com/questions/40100348

    using (MySqlConnection lconn = new MySqlConnection(connString))
    {
        lconn.Open();
        MySqlCommand cmd = new MySqlCommand();
        string sXX = @"DROP PROCEDURE IF EXISTS asdf7; 
        CREATE PROCEDURE asdf7() 
        BEGIN 
        SET @sqlstmt = 'dog';  
        IF 1=1 THEN 
          SET @sqlstmt = CONCAT('qwerty ',1,2); 
        END IF; 
        SELECT @sqlstmt; 
        END";  
        cmd.Connection = lconn;
        cmd.CommandText = sXX;
        cmd.ExecuteNonQuery();
    }
}

以及它成功保存到db的截图：

另请注意我在您提问的评论中提到的内容。在c＃端使用简单的CONCAT可以很容易地将变量插入到像tablename这样的查询中。

如果存在与Allow User Variables=True相关的安全风险（我并不怀疑），请将此连接字符串调整仅与此例程相关，而不是全局。

这里的另一个问题是至少在我的测试中不需要DELIMITER（类似于PHPMyAdmin和SQLFiddle）。与MySQL Workbench / Navicat / SQLYog（可能）/ Toad（可能）

不同

C＃命令执行期间遇到致命错误

1 个答案: