oracl 和db2 常用语法比较： 1、取前N条记录 Oracle：Select * from TableName where rownum <= N; DB2：Select * from TableName fetch first N rows only; 2、取得系统日期 Oracle：Select sysdate from dual; DB2：Select current timestamp from sysibm.sysdummy1; 3、空值转换 Oracle：Select
chan算法CHAN AND HO: A SIMPLE AND EFFICIENT ESTIMATOR FOR HYPERBOLIC LOCATION SYSTEM
y=yo. In the next iteration, Io and yo are then set to o+A where
and yo +Ay. The whole process is repeated again until A and
Ay are sufficiently small. This method has
