insert into [ULGP_CARES TEST].[dbo].[person](date_of_birth)
select [Dtest].[dbo].[ContactBase].[BirthDate]
from [Dtest].[dbo].[ContactBase]
where
[Dtest].[dbo].[ContactBase].[FirstName]=[ULGP_CARES TEST].[dbo].[person].[first_name]
and
[Dtest].[dbo].[ContactBase].[MiddleName]=[ULGP_CARES TEST].[dbo].[person]. [middle_name]
and
[Dtest].[dbo].[ContactBase].[LastName]=[ULGP_CARES TEST].[dbo].[person].[last_name]
while trying to run the above query i am getting the following error "Msg 4104, Level 16, State 1, Line 6 The multi-part identifier "ULGP_CARES TEST.dbo.person.first_name" could not be bound. Msg 4104, Level 16, State 1, Line 9 The multi-part identifier "ULGP_CARES TEST.dbo.person.middle_name" could not be bound. Msg 4104, Level 16, State 1, Line 11 The multi-part identifier "ULGP_CARES TEST.dbo.person.last_name" could not be bound."
how to solve this?