How can I update a particular column in a 7 million record table, where it has many conditions to go.

Question

I am designing a table, for which I am loading the data into my table from different tables by giving joins. But I have Status column, for which I have about 16 different statuses from different tables, now for each case I have a condition, if it satisfies
then the particular status will show in status column, in that way I need to write the query as 16 different cases. 
Now, my question is what is the best way to write these cases for the to satisfy all the conditions and also get the data quickly to the table. As the data we are getting is mostly from big tables about 7 million records. And if we give the logic as case
it will scan for each case and about 16 times it will scan the table, How can I do this faster? Can anyone help me out

Answer 1

Here is the code I have written to get the data from temp tables which are taking records from 7 millions table with  filtering records of year 2013. This is taking more than an hour to run. Iam posting the part of code which is running slow, mainly
the part of Status column.
SELECT
z.SYSTEMNAME
--,Case when ZXC.[Subsystem Name] <> 'NULL' Then zxc.[SubSystem Name]
--else NULL
--End AS SubSystemName
, CASE
WHEN z.TAX_ID IN
(SELECT DISTINCT zxc.TIN
FROM .dbo.SQS_Provider_Tracking zxc
WHERE zxc.[SubSystem Name] <> 'NULL'
THEN
(SELECT DISTINCT [Subsystem Name]
FROM .dbo.SQS_Provider_Tracking zxc
WHERE z.TAX_ID = zxc.TIN)
End As SubSYSTEMNAME
,z.PROVIDERNAME
,z.STATECODE
,z.TAX_ID
,z.SRC_PAR_CD
,SUM(z.SEQUEST_AMT) Actual_Sequestered_Amt
, CASE
WHEN z.SRC_PAR_CD IN ('E','O','S','W')
THEN 'Nonpar Waiver'
-- --Is Puerto Rico of Lifesynch
WHEN z.TAX_ID IN
(SELECT DISTINCT a.TAX_ID
FROM .dbo.SQS_NonPar_PR_LS_TINs a
WHERE a.Bucket <> 'Nonpar'
THEN
(SELECT DISTINCT a.Bucket
FROM .dbo.SQS_NonPar_PR_LS_TINs a
WHERE a.TAX_ID = z.TAX_ID)
--**Amendment Mailed**
WHEN z.TAX_ID IN
(SELECT DISTINCT b.PROV_TIN
FROM .dbo.SQS_Mailed_TINs_010614 b WITH (NOLOCK )
where not exists (select * from dbo.sqs_objector_TINs t where b.PROV_TIN = t.prov_tin))
and z.Hosp_Ind = 'P'
THEN
(SELECT DISTINCT b.Mailing
FROM .dbo.SQS_Mailed_TINs_010614 b
WHERE z.TAX_ID = b.PROV_TIN
-- --**Amendment Mailed Wave 3-5**
WHEN z.TAX_ID In
(SELECT DISTINCT
qz.PROV_TIN
FROM
[SQS_Mailed_TINs] qz
where qz.Mailing = 'Amendment Mailed (3rd Wave)'
and not exists (select * from dbo.sqs_objector_TINs t where qz.PROV_TIN = t.prov_tin))
and z.Hosp_Ind = 'P'
THEN 'Amendment Mailed (3rd Wave)'
WHEN z.TAX_ID IN
(SELECT DISTINCT
qz.PROV_TIN
FROM
[SQS_Mailed_TINs] qz
where qz.Mailing = 'Amendment Mailed (4th Wave)'
and not exists (select * from dbo.sqs_objector_TINs t where qz.PROV_TIN = t.prov_tin))
and z.Hosp_Ind = 'P'
THEN 'Amendment Mailed (4th Wave)'
WHEN z.TAX_ID IN
(SELECT DISTINCT
qz.PROV_TIN
FROM
[SQS_Mailed_TINs] qz
where qz.Mailing = 'Amendment Mailed (5th Wave)'
and not exists (select * from dbo.sqs_objector_TINs t where qz.PROV_TIN = t.prov_tin))
and z.Hosp_Ind = 'P'
THEN 'Amendment Mailed (5th Wave)'
-- --**Top Objecting Systems**
WHEN z.SYSTEMNAME IN
('ADVENTIST HEALTH SYSTEM','ASCENSION HEALTH ALLIANCE','AULTMAN HEALTH FOUNDATION','BANNER HEALTH SYSTEM')
THEN 'Top Objecting Systems'
WHEN z.TAX_ID IN
(SELECT DISTINCT
h.TAX_ID
FROM
#HIHO_Records h
INNER JOIN .dbo.SQS_Provider_Tracking obj
ON h.TAX_ID = obj.TIN
AND obj.[Objector?] = 'Top Objector'
WHERE z.TAX_ID = h.TAX_ID
OR h.SMG_ID IS NOT NULL
)and z.Hosp_Ind = 'H'
THEN 'Top Objecting Systems'
-- --**Other Objecting Hospitals**
WHEN (z.TAX_ID IN
(SELECT DISTINCT
h.TAX_ID
FROM
#HIHO_Records h
INNER JOIN .dbo.SQS_Provider_Tracking obj
ON h.TAX_ID = obj.TIN
AND obj.[Objector?] = 'Objector'
WHERE z.TAX_ID = h.TAX_ID
OR h.SMG_ID IS NOT NULL
)and z.Hosp_Ind = 'H')
THEN 'Other Objecting Hospitals'
-- --**Objecting Physicians**
WHEN (z.TAX_ID IN
(SELECT DISTINCT
obj.TIN
FROM .dbo.SQS_Provider_Tracking obj
WHERE obj.[Objector?] in ('Objector','Top Objector')
and z.TAX_ID = obj.TIN
and z.Hosp_Ind = 'P')
THEN 'Objecting Physicians'
--****Rejecting Hospitals****
WHEN (z.TAX_ID IN
(SELECT DISTINCT
h.TAX_ID
FROM
#HIHO_Records h
INNER JOIN .dbo.SQS_Provider_Tracking obj
ON h.TAX_ID = obj.TIN
AND obj.[Objector?] = 'Rejector'
WHERE z.TAX_ID = h.TAX_ID
OR h.SMG_ID IS NOT NULL
)and z.Hosp_Ind = 'H')
THEN 'Rejecting Hospitals'
--****Rejecting Physciains****
WHEN
(z.TAX_ID IN
(SELECT DISTINCT
obj.TIN
FROM .dbo.SQS_Provider_Tracking obj
WHERE z.TAX_ID = obj.TIN
AND obj.[Objector?] = 'Rejector')
and z.Hosp_Ind = 'P')
THEN 'REjecting Physicians'
----**********ALL OBJECTORS SHOULD HAVE BEEN BUCKETED AT THIS POINT IN THE QUERY**********
-- --**Non-Objecting Hospitals**
WHEN z.TAX_ID IN
(SELECT DISTINCT
h.TAX_ID
FROM
#HIHO_Records h
WHERE
(z.TAX_ID = h.TAX_ID)
OR h.SMG_ID IS NOT NULL)
and z.Hosp_Ind = 'H'
THEN 'Non-Objecting Hospitals'
-- **Outstanding Contracts for Review**
WHEN z.TAX_ID IN
(SELECT DISTINCT
qz.PROV_TIN
FROM
[SQS_Mailed_TINs] qz
where qz.Mailing = 'Non-Objecting Bilateral Physicians'
AND z.TAX_ID = qz.PROV_TIN)
Then 'Non-Objecting Bilateral Physicians'
When z.TAX_ID in
(select distinct
p.TAX_ID
from dbo.SQS_CoC_Potential_Mail_List p
where p.amendmentrights <> 'Unilateral'
AND z.TAX_ID = p.TAX_ID)
THEN 'Non-Objecting Bilateral Physicians'
WHEN z.TAX_ID IN
(SELECT DISTINCT
qz.PROV_TIN
FROM
[SQS_Mailed_TINs] qz
where qz.Mailing = 'More Research Needed'
AND qz.PROV_TIN = z.TAX_ID)
THEN 'More Research Needed'
WHEN z.TAX_ID IN (SELECT DISTINCT qz.PROV_TIN FROM [SQS_Mailed_TINs] qz where qz.Mailing = 'Objector' AND qz.PROV_TIN = z.TAX_ID)
THEN 'ERROR'
else 'Market Review/Preparing to Mail'
END AS [STATUS Column]
Please suggest on this