ORA08002: sequence SEQ_T_CARREG.CURRVAL is not yet defined in this session

同事来问测试环境上的一个sequence.currval 为什么取不到当前值。我说你试试nextval就能取到了。

metalink ORA-8002 When Selecting CURRVAL From Sequence [ID 1019173.102]

文章中说到：

Before you can access CURRVAL for a sequence, you must first initialize the
sequence with NEXTVAL.

下面做个小的实验：

SQL> CREATE SEQUENCE t_sequence START WITH 1000;

Sequence created

创建序列后，直接使用currval取序列的当前记录，返回错误：ORA-08002

SQL> SELECT t_sequence.CURRVAL FROM DUAL;

SELECT t_sequence.CURRVAL FROM DUAL

ORA-08002: sequence T_SEQUENCE.CURRVAL is not yet defined in this session

SQL> SELECT t_sequence.nextval FROM DUAL;

NEXTVAL
----------
1000

SQL> SELECT t_sequence.CURRVAL FROM DUAL;

CURRVAL
----------
1000

SQL> SELECT t_sequence.nextval FROM DUAL;

NEXTVAL
----------
1001