Instruction
Very well done! Now, how about sequences? Can they be modified or removed? It turns out that they can! Let's say we have a sequence like this:
CREATE SEQUENCE standard_seq START WITH 1 INCREMENT BY 1;
The sequence generates subsequent integers for us. At some point, however, we deleted all rows with auto-generated values and we'd like the sequence to start generating numbers from 1 again. We can use the following syntax:
ALTER SEQUENCE standard_seq START WITH 1 RESTART;
The query above first sets the new starting value for sequence standard_seq to 1 and then uses RESTART to actually reset the current value to the starting value. Sound complicated? You can also use the simplified syntax:
ALTER SEQUENCE standard_seq RESTART WITH 1;
The code above works the same – it simply sets the current sequence value to 1. You can also restart a sequence using any other value. If you want to start over from 100, you just need to use:
ALTER SEQUENCE standard_seq RESTART WITH 100;
Exercise
The agency has created the sequence below:
CREATE SEQUENCE artist_numbers START WITH 1 INCREMENT BY 2;
Some values have already been generated. Your task is to start the sequence over from 1.
