Private Sub Form_Load()Dim i As IntegerDim rst As DAO.RecordsetSet rst = CurrentDb.OpenRecordset("SELECT * FROM menu;") '以要链接的表建立记录集If rst.RecordCount = 0 Then MsgBox "表中无数据!程序终止.": Exit Sub '如果链接表无数据i = 1rst.MoveFirst '记录首While Not rs
在用spark的yarn-cluster模式跑fpgrowth进行频繁项集挖掘的时候,报如下错误: ERROR yarn.ApplicationMaster: User class threw exception: java.lang.IllegalAccessError: tried to access method com.google.common.base.Stopwatch.<init>()V from class org.apache.hadoop.mapred.FileInput
access随机读取数时 用order by rnd(id) 发现每次获取的数据顺序都是一致的,必须要加上随机数才可以,如下: Random r = new Random(); int sj = r.Next(100,10000000); sqlstr = "select top 20 * from question order by rnd("+-sj+"*id)"; sqlserver 随机数:order by