SQL> select sal,comm from emp 2 where sal<2000; SAL COMM---------- ---------- 800 1600 300 1250 500 1250 1400 1500 0 1100 950 13008 rows selected.SQL> select sal as salary,comm as commission from emp 2 where salary<2000;where salary<2000 *ERROR at line 2:ORA-00904: "SALARY": invalid identifierSQL> select * from 2 ( 3 select sal as salary,comm as commission from emp 4 ) x 5 where salary<2000; SALARY COMMISSION---------- ---------- 800 1600 300 1250 500 1250 1400 1500 0 1100 950 13008 rows selected.SQL> select sal,comm from emp 2 where sal<200 你的当前访问异常,请进行认证后继续阅读剩余内容。 提交