一些有用的SQL语句

1：导入数据

imp80 system/manager@orcl file=D:\TEMP\dbfile1.dmp full=n fromuser=yh1 touser=yh2;

2：多表更新

update table1 a set a.column1=(select b.column1 from table2 b

where a.column2=b.2column2)

where a.column3 is not null;