SQL Table update based on values within table - tsql

Question

I am looking to update rows in a table with values from other rows on the same table based on a common value.
In the table below I need to update the rows where 'Effective', 'End' and 'Enddate' are blank with the values from the row with the same IRN and FRN and where Name='[FCA CF] Functions requiring qualifications'.
So row 1 would inherit the data from row 2, row 3 from row 4, etc.
How can I do that please?
Thanks.

Answer 1

Looks like a regular update statement with a self join should do it.
Sample data
create table data
(
IRN int,
FRN int,
Name nvarchar(50),
Effective bit,
Ended bit,
EndDate date
);
insert into data (IRN, FRN, Name, Effective, Ended, EndDate) values
(100, 200, 'Something else?', null, null, null),
(100, 200, '[FCA CF] Functions requiring qualifications', 1, 1, '2020-12-06'),
(100, 200, 'Not what we are looking for', 0, 0, null),
(100, 300, 'Do not touch, different FRN', null, null, null);
Solution
update d1
set d1.Effective = d2.Effective,
d1.Ended = d2.Ended,
d1.EndDate = d2.EndDate
from data d1
join data d2
on d2.IRN = d1.IRN
and d2.FRN = d1.FRN
where d1.Effective is null
and d1.Ended is null
and d1.EndDate is null
and d2.Name = '[FCA CF] Functions requiring qualifications';
Result
IRN FRN Name Effective Ended EndDate
--- --- ------------------------------------------- --------- ----- ----------
100 200 Something else? True True 2020-12-06
100 200 [FCA CF] Functions requiring qualifications True True 2020-12-06
100 200 Not what we are looking for False False null
100 300 Do not touch, different FRN null null null
Fiddle to see it in action.