How to query UUID for postgres

Question

I'd like to use UUID as an identifier, provide the first 8 digits to find out if it exists in the database.

normally I can do this without a problem:

select * from TABLE where id = 'e99aec55-9e32-4c84-aed2-4a0251584941'::uuid

but this gives me error:

select * from TABLE where id LIKE 'e99aec55%@'::uuid

error:

ERROR:  invalid input syntax for uuid: "e99aec55%@"
LINE 1: select * from TABLE where id LIKE 'e99aec55...
                                              ^
Query failed
PostgreSQL said: invalid input syntax for uuid: "e99aec55%@"

Is there a way to query first n digits for a UUID type in postgresql?

Answer 1

Since you are searching for the highest bits of uuids, you can actually use between (because uuid comparison is well-defined in PostgreSQL):

...
where some_uuid between 'e99aec55-0000-0000-0000-000000000000'
                    and 'e99aec55-ffff-ffff-ffff-ffffffffffff'

Answer 2

UUIDs are not stored as strings in Postrges, they are stored as a 16-byte long binary values. So the only way to query it in the way you want is to convert it to string at first, but the performance of such conversion will be worser than just performing an equality comparison.

Also you will need to maintain an index on those string representation of the UUIDs, so it just doesn't make sense.