我正在使用它来查询我在 c#.net mysql 连接中达到 20 的位置。这个查询需要永远执行,当我在 MySQL shell 中运行它时需要 3 分钟。所有其他查询运行良好。
string sqlQuery = "(SELECT TimeStamp, AVG(FwdHr), W FROM Meter_Data " +
"WHERE TimeStamp Between " +
(timeSt[0] - window).ToString() +
" AND " + (timeSt[0] + window).ToString() +
" AND DeviceID = '"+deviceId+"')";
for (int i = 1; i < timeSt.Count; i++)
{
sqlQuery = sqlQuery+ " UNION (SELECT TimeStamp, AVG(FwdHr), W
FROM Meter_Data WHERE TimeStamp Between " +
(timeSt[i] - window).ToString() + " AND " +
(timeSt[i] + window).ToString() +
" AND DeviceID = '" + deviceId + "')";
}