I want to insert value to Postgres
If I have enum type in a table and I want to change the input value is not in the list of enum
like
create type us_state as enum ('AL', ..., 'NULL');
insert into user (name, state)
values ('Bob', 'AA')
conflict on state is not valid us_state update value = 'NULL'
how can I use conditional insert or update the value while inserting?
As far as concerned, on conflict does not recognize enum violations. The INSERT documentation says:
The optional
ON CONFLICTclause specifies an alternative action to raising a unique violation or exclusion constraint violation error.
Unfortunately an enum type does not fall in that category (same applies to check constraints, which otherwise could have been a possible solution here).
We could resort the trick of listing the enum values with enum_range(), then using that in a conditional expression:
insert into users(name, state)
select
name,
case when state = any(enum_range(null::us_state)::name[])
then state::us_state
end
from (values ('Bob', 'AA')) t(name, state)
Note that this produces a NULL value when the given value does not exists in the enum, rather than an arbitratry string such as 'NULL'; this looks to me like the proper way to represent unmatched values.
create type us_state as enum ('AL', 'WA');
create table users(name text, state us_state);
-- an attempt with "on conflict"
insert into users (name, state) values ('Bob', 'AA') on conflict(state) do nothing
-- ERROR: invalid input value for enum us_state: "AA";
-- LINE 1: insert into users (name, state) values ('Bob', 'AA') on conf...
-- new query
insert into users(name, state)
select
name,
case when state = any(enum_range(null::us_state)::name[])
then state::us_state
end
from (values ('Bob', 'AA'), ('Bill', 'AL')) t(name, state);
-- 2 rows affected
select * from users;
name | state :--- | :---- Bob | null Bill | AL