ORA-02287: 此处不允许序号

 select test.sequence.nextval,mgr,sum(sal) from emp group by mgr ORA-02287: 此处不允许序号 果然，在外面再包一层就可以了SQL> select test_sequence.nextval,mgr,sm from (select mgr,sum(sal) sm from emp group by mgr );    NEXTVAL   MGR         SM---------- ----- ----------        27  7839       8275        28  7782       1300        29  7698       6550        30  7902       5800        31  7566       6000        32  7788       1100 6 rows selected 看来序列使用时有限制的看到书上说有这么多限制Restrictions on Sequence Values You cannot use CURRVAL and NEXTVAL in thefollowing constructs:■ A subquery in a DELETE, SELECT, or UPDATE statement■ A query of a view or of a materialized view■ A SELECT statement with the DISTINCT operator■ A SELECT statement with a GROUP BY clause or ORDER BY clause    --这个就是我遇到的那种情况■ A SELECT statement that is combined with another SELECT statement with theUNION, INTERSECT, or MINUS set operator■ The WHERE clause of a SELECT statement■ The DEFAULT value of a column in a CREATE TABLE or ALTER TABLE statement■ The condition of a CHECK constrain