SQL left join for inactive records - sql

Question

I have 2 tables. One of them has actual names and the other one has nicknames used by those people.
CREATE TABLE [dbo].[Customer](
[id] [int] IDENTITY(1,1) NOT NULL,
[firstName] [varchar](50) NULL,
[lastName] [varchar](50) NULL,
[active] [bit] NULL
) ON [PRIMARY]
GO
CREATE TABLE [dbo].[CustomerAKA](
[id] [int] NULL,
[akaFirstName] [varchar](50) NULL,
[akaLastName] [varchar](50) NULL
) ON [PRIMARY]
GO
SET IDENTITY_INSERT [dbo].[Customer] ON
INSERT [dbo].[Customer] ([id], [firstName], [lastName], [active]) VALUES (1, N'Op', N'Test', 0)
INSERT [dbo].[Customer] ([id], [firstName], [lastName], [active]) VALUES (2, N'M', N'J', 1)
INSERT [dbo].[Customer] ([id], [firstName], [lastName], [active]) VALUES (3, N'John', N'Doe', 1)
SET IDENTITY_INSERT [dbo].[Customer] OFF
INSERT [dbo].[CustomerAKA] ([id], [akaFirstName], [akaLastName]) VALUES (1, N'Hello', N'Test')
INSERT [dbo].[CustomerAKA] ([id], [akaFirstName], [akaLastName]) VALUES (1, N'Mahalo', N'Test')
INSERT [dbo].[CustomerAKA] ([id], [akaFirstName], [akaLastName]) VALUES (3, N'Jonny', N'Doe')
My query is :
select *
from dbo.Customer c1
left join dbo.CustomerAKA c2 on c2.id = c1.id
where not exists ( select *
from dbo.Customer c
where c.id = c1.id
and c.active = 0 )
Even though Op Test is not active, I still want to get the nicknames for him:
1 Hello Test
1 Mahalo Test
So my output should be :
M J
John Doe
Jonny Doe
Hello Test
Mahalo Test
Any ideas?

Answer 1

I think you want union all:
select c.firstname, c.lastname
from customer c
union all
select ca.akafirstname, c.akalastname
from customeraka ca join
customer c
on ca.id = c.id
where c.active = 1;

Answer 2

Try this:
/*
WITH
Customer (id, firstName, lastName, active) AS
(
VALUES
(1, 'Op', 'Test', 0)
, (2, 'M', 'J', 1)
, (3, 'John', 'Doe', 1)
)
, CustomerAKA (id, akaFirstName, akaLastName) AS
(
VALUES
(1, 'Hello', 'Test')
, (1, 'Mahalo', 'Test')
, (3, 'Jonny', 'Doe')
)
*/
SELECT firstName, lastName
FROM Customer
WHERE active = 1
UNION ALL
SELECT c2.akaFirstName AS firstName, c2.akaLastName AS lastName
FROM CustomerAKA c2
JOIN Customer c1 ON c1.id=c2.id;

Answer 3

Not sure about what you want
But seems something like
select *
from dbo.Customer c1
left join dbo.CustomerAKA c2 on c2.id = c1.id
where c1.active = 1 or (c1.firstname = "Op" and c1.lastname = "Test")
Order by c1.active desc
Or like
select
coalesce(c2.firstname, c1.firstname) as firstname,
coalesce(c2.lastname, c1.lastname) as lastname
from dbo.Customer c1
Left outer join dbo.CustomerAKA c2 on c2.id = c1.id
Order by c1.active desc