Descending Sequences
Jim_Knicely
- Select Field - Administrator
The default increment for a Vertica sequence 1. But you can also create a sequence that has a negative increment so that you can have a count down.
Example:
dbadmin=> CREATE SEQUENCE up_seq;
CREATE SEQUENCE
dbadmin=> SELECT up_seq.NEXTVAL;
NEXTVAL
---------
1
(1 row)
dbadmin=> SELECT up_seq.NEXTVAL;
NEXTVAL
---------
2
(1 row)
dbadmin=> SELECT up_seq.NEXTVAL;
NEXTVAL
---------
3
(1 row)
dbadmin=> CREATE SEQUENCE down_seq START WITH 3 INCREMENT BY -1;
CREATE SEQUENCE
dbadmin=> SELECT down_seq.NEXTVAL;
NEXTVAL
---------
3
(1 row)
dbadmin=> SELECT down_seq.NEXTVAL;
NEXTVAL
---------
2
(1 row)
dbadmin=> SELECT down_seq.NEXTVAL;
NEXTVAL
---------
1
(1 row)
dbadmin=> SELECT down_seq.NEXTVAL;
ERROR 4705: Sequence exceeded min value
Helpful Links:
https://www.vertica.com/docs/9.2.x/HTML/Content/Authoring/AdministratorsGuide/Sequences/Sequences.htm
https://www.vertica.com/docs/9.2.x/HTML/Content/Authoring/SQLReferenceManual/Statements/CREATESEQUENCE.htm
Have fun!
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