How to combine two queries keeping all results from one

I have a table of Accounts:

and a table of CurrentAccounts:

The desired result of combining these two tables is:

I have achieved the desired result with this SQL:

DECLARE @T1 AS TABLE (ID INT, Name VARCHAR(20), Active BIT);
    
INSERT INTO @t1 
    SELECT ID, Name, 0 
    FROM Accounts;

UPDATE @T1 
SET Active = 1 
WHERE ID IN (SELECT ID FROM CurrentAccounts);
    
SELECT * FROM @T1

However, there must be a more efficient way of achieving the same result.

A simple sub-query will give you the results you require:

create table Account (AccountId int, Name varchar(128));
create table CurrentAccount (AccountId int);

insert into Account (AccountId, Name)
values
(1, 'Account A'),
(2, 'Account B'),
(3, 'Account C'),
(4, 'Account D'),
(5, 'Account E');

insert into CurrentAccount (AccountId)
values
(2),
(4);

select
    *
    , case when exists (select 1 from CurrentAccount ca where ca.AccountId = a.AccountId) then 'True' else 'False' end Active
from Account a;

db<>fiddle