范例:
//返回SZ000002(万科A)从20110905到20110909的区间最低成交量
SetSysParam(PN_Stock(),'SZ000002');
SetSysParam(PN_Rate(),1);
SetSysParam(PN_RateDay(),inttodate(20110909));
BegT:=inttodate(20110905);
EndT:=inttodate(20110909);
return StockLowVol(BegT,EndT);
//结果:17932168