C#访问数据库update报错
代码粘贴如下：
for (int j = 0; j < row; j++)
{
//找出原始值
string find_value = "select * from sensor_running where (date(dt) between str_to_date('2012-08-01', '%Y-%m-%d') and str_to_date('2012-08-07', '%Y-%m-%d')) and weekday(date(dt)) < 5 and (time(dt) = '23:30:00') and sub_id = " + id[j];
DataSet ds_week_morning = new DataSet();
DataTable dt_week_morning = new DataTable();
MySqlDataAdapter da_week_morning = new MySqlDataAdapter(find_value,conn);
da_week_morning.Fill(ds_week_morning,id[j].ToString());
dt_week_morning = ds_week_morning.Tables[id[j].ToString()];
for (int k = 0; k < dt_week_morning.Rows.Count; k++)
{
//为凌晨的数据赋以与前一天深夜一样的值
string set_value = "UPDATE sensor_running SET value = " + dt_week_morning.Rows[k][1] + "WHERE sub_id = " + id[j] + " AND date(dt) = date_add(date(str_to_date('" + dt_week_morning.Rows[k][2].ToString() + "','%Y/%m/%d %H:%i:%d')), interval 2 day) and hour(dt) between 0 and 7";
MySqlCommand update = connectMySQL.getMySqlCommand(set_value, conn);
update.ExecuteNonQuery();
Console.Write("影响{0}行\n", update.ExecuteNonQuery());
}
}
运行程序时，update.ExecuteNonQuery();处报错：You have an error in your SQL syntax。但是将查询语句直接用于mysql时并没有出错，可以update。应该不是语法错误这么简单的问题，麻烦求问高手这个update错在哪里
WHERE sub_id = " + id[j] + " AND date(dt) = date_add(date(str_to_date('" + dt_week_morning.Rows[k][2].ToString() + "','%Y/%m/%d %H:%i:%d')), interval 2 day) and hour(dt) between 0 and 7";
红色部分少空格。另外你可以调试，把set_value 拿到sql查询分析器执行下看看是否正确
[解决办法]
把你的sql语句拿到数据库里执行一下看看有没有错误
