/// <summary>/// 执行查询语句，返回DataSet/// </summary>/// <param name="SQLString">查询语句</param>/// <returns>DataSet</returns>public   DataSet Query(string SQLString, params SqlParameter[] cmdParms){using (SqlConnection connection = new SqlConnection(connectionString)){SqlCommand cmd = new SqlCommand();PrepareCommand(cmd, connection, null, SQLString, cmdParms);using (SqlDataAdapter da = new SqlDataAdapter(cmd)){DataSet ds = new DataSet();try{da.Fill(ds, "ds");cmd.Parameters.Clear();}catch (System.Data.SqlClient.SqlException ex){throw new Exception(ex.Message);}return ds;}}}private   void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, string cmdText, SqlParameter[] cmdParms){if (conn.State != ConnectionState.Open)conn.Open();cmd.Connection = conn;cmd.CommandText = cmdText;if (trans != null)cmd.Transaction = trans;cmd.CommandType = CommandType.Text;//cmdType;if (cmdParms != null){foreach (SqlParameter parameter in cmdParms){if ((parameter.Direction == ParameterDirection.InputOutput || parameter.Direction == ParameterDirection.Input) &&(parameter.Value == null)){parameter.Value = DBNull.Value;}cmd.Parameters.Add(parameter);}}}string connectionString = "Data Source=192.168.42.97;Initial Catalog=DataCompare;User ID=sa;Password=sa";public DataTable QueryBigFQCY(string datatype){string cmdText = "select   distinct pici from InputData  where and createtime >='2011-09-27 10:40:54.293' order by pici desc";DataTable dt = new DataTable();SqlParameter[] parm = new SqlParameter[] { new SqlParameter("@datetype", datatype) };try{DataSet ds = Query(cmdText, parm);if (ds != null && ds.Tables.Count > 0){dt = ds.Tables[0];}}catch (Exception ex){throw new Exception(ex.Message);}return dt;}