查询Sequence
语法
SHOW SEQUENCES
示例
请在命令行输入如下代码：
mysql> SHOW SEQUENCES;
返回结果如下：
+------+--------+------------+------------+------------+--------------+------------+-------------+-------+--------+ | NAME | VALUE | UNIT_COUNT | UNIT_INDEX | INNER_STEP | INCREMENT_BY | START_WITH | MAX_VALUE | CYCLE | TYPE | +------+--------+------------+------------+------------+--------------+------------+-------------+-------+--------+ | seq1 | 100000 | 1 | 0 | 100000 | N/A | N/A | N/A | N/A | GROUP | | seq2 | 400000 | 3 | 1 | 100000 | N/A | N/A | N/A | N/A | GROUP | | seq3 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | TIME | | seq4 | 1006 | N/A | N/A | N/A | 2 | 1000 | 99999999999 | N | SIMPLE | +------+--------+------------+------------+------------+--------------+------------+-------------+-------+--------+ 4 rows in set (0.00 sec)
说明 返回结果中的TYPE列，显示的是Sequence类型的缩写。
获取显式Sequence值
语法
[<schema_name>.]<sequence name>.NEXTVAL
示例
- 方法一请在命令行输入如下代码：
mysql> SELECT sample_seq.nextval FROM dual;
- 返回结果如下：
+--------------------+ | SAMPLE_SEQ.NEXTVAL | +--------------------+ | 101001 | +--------------------+ 1 row in set (0.04 sec)
- 方法二请在命令行输入如下代码：
mysql> INSERT INTO some_users (name,address,gmt_create,gmt_modified,intro) VALUES ('sun',sample_seq.nextval,now(),now(),'aa');
- 说明
- 该方法是把sample_seq.nextval当做一个值写入了 SQL中。
- 如果建表时已经指定了AUTO_INCREMENT参数，INSERT时不需要指定自增列，可以让PolarDB-X自动维护。
批量获取Sequence值
语法
批量获取Sequence值的语法如下：
SELECT [<schema_name>.]<sequence name>.NEXTVAL FROM DUAL WHERE COUNT = <numeric value>
示例
请在命令行输入如下代码：
mysql> SELECT sample_seq.nextval FROM dual WHERE count = 10;
返回结果如下：
+--------------------+ | SAMPLE_SEQ.NEXTVAL | +--------------------+ | 101002 | | 101003 | | 101004 | | 101005 | | 101006 | | 101007 | | 101008 | | 101009 | | 101010 | | 101011 | +--------------------+ 10 row in set (0.04 sec)
