TSQL - Updating column based on bit column - sql-server

Question

I have an identity column in my table [ID]. I also have a computed column that is based on the identity column like so;
create table [dbo].[tblMaster] (
ID bigint identity(1,1),
GlobalFamilyUniqueID int,
DupeIdentifier as cast('EDME' + RIGHT('00000000'+ISNULL(cast([ID] as nvarchar(max)),''),8) as nvarchar(30)),
ControlNumber nvarchar(30),
NuixGuid nvarchar(50),
TopLvlGuid nvarchar(50),
ParentGuid nvarchar(50),
CustodianArtifactID int,
IsGlobalFamilyUnique int,
IsCustodianFamilyUnique int,
IsItemUnique int,
ItemUniqueDupID nvarchar(100),
IsChild int,
GroupIdentifier nvarchar(100),
DatasourceID int,
MD5Hash nvarchar(32),
GlobalFamilyDupID nvarchar(100),
CustodianFamilyDupId nvarchar(100),
ExportSessionID nvarchar(100)
)
I want to be update the ControlNumber column based on the IsGlobalFamilyUnique column. At the minute, DupeIdentifier will have a value regardless if IsGlobalFamilUnique is 1 or 0. I need ControlNumber to have an incremental value based on the last value in the ControlNumber field (I created another column called GlobalFamilyUnqiueID as a "counter" column) , but only when IsGlobalFamilUnique is 1.
This is where I am at so far;
update x
set
GlobalFamilyUniqueID = [ProposedGlobalFamilyUniqueID],
ControlNumber = [ProposedControlNumber]
from(
Select top 10 [id],
DupeIdentifier,
-- ControlNumber,
isglobalfamilyunique,
--GlobalFamilyUniqueID,
GlobalFamilyUniqueID,
Row_Number() Over(Order By [id]) [ProposedGlobalFamilyUniqueID],
ControlNumber,
'TEST' + RIGHT('00000000'+ISNULL(cast(Row_Number() Over(Order By [id]) as nvarchar(30)),''),8) [ProposedControlNumber]
From dbo.tblMaster mstr1
where IsGlobalFamilyUnique = 1 and ControlNumber is null
)x
The problem is that when the code is run again ProposedGlobalFamilyUniqueID will start at 1 again. It should start at the last value of ProposedGlobalFamilyUniqueID in dbo.tblMaster. I assume this is because I am limiting the query to where ControlNumber is null, but I don't know how to get around this.
This is an example of the code working successfully the first time its run:
The end result should be sequential ControlNumber values where IsGlobalFamilyUnique = 1
Example Data
declare #test table (
ID bigint identity(1,1),
GlobalFamilyUniqueID int,
DupeIdentifier as cast('EDME' + RIGHT('00000000'+ISNULL(cast([ID] as nvarchar(max)),''),8) as nvarchar(30)),
ControlNumber nvarchar(30),
MD5Hash nvarchar(32),
IsGlobalFamilyUnique bit
)
insert into #test (MD5Hash, IsGlobalFamilyUnique)values
--1
('ABC', 1),
--2
('DEF', 1),
--3
('GHI', 1),
--4
('JKL', 1),
--5
('ABC', 0),
--6
('XXX', 1)
The result should be;

Answer 1

Keep ControlNumber field as a number, try not to make it varchar because it will be not be able to calculate.
First of all remove all existing control number values before trying script.
Then,try this one:
DECLARE #max as bigint
SELECT #max = Max(id)
FROM tblMaster
Select [id],
DupeIdentifier,
-- ControlNumber,
isglobalfamilyunique,
--GlobalFamilyUniqueID,
GlobalFamilyUniqueID,
#max + Row_Number() Over(Order By [id]) [ProposedGlobalFamilyUniqueID],
ControlNumber
From dbo.tblMaster mstr1
where IsGlobalFamilyUnique = 1 and ControlNumber is null
update x
set
GlobalFamilyUniqueID = [ProposedGlobalFamilyUniqueID],
ControlNumber = x.Proposed_Control_Number
from(
Select [id],
DupeIdentifier,
-- ControlNumber,
isglobalfamilyunique,
--GlobalFamilyUniqueID,
GlobalFamilyUniqueID,
Row_Number() Over(Order By [id]) [ProposedGlobalFamilyUniqueID],
ControlNumber,
#max + Row_Number() Over(Order By [id]) as Proposed_Control_Number
From dbo.tblMaster mstr1
Where IsGlobalFamilyUnique = 1 and ControlNumber is null
)x