关于oracle的序列调用问题

在调用序列的CURRVAL 和NEXTVAL方法时，在一下SQL结构禁止使用

• 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

• A SELECT statement that is combined with another SELECT statement with the UNION, 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 constraint