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Update A Column based on results of another column

In the same table "PropertyCalcs", I am try to update a column based a minimum value of another column.

I have PropertyID, OrderNumber, and First Inspection Date as columns.

For each ProptertyID, I need SQL to find the min(OrderNumber) and then write 'First Inspection Date' in the First Inspection Date column, when it finds the minimum OrderNumber for that PropertyID.

If you have any questions, please let me know and I'll be happy to answer them.
0
Erik Hauser
Asked:
Erik Hauser
1 Solution
 
Jim HornMicrosoft SQL Server Developer, Architect, and AuthorCommented:
Air code.  I also do my own stunts..
UPDATE your_table
SET [First Inspection Date] = 'First Inspection Date'
FROM your_table yt
JOIN (
   SELECT ProptertyID, min(OrderNumber) as min_order_number
   FROM your_table
   GROUP BY PropertyID) yt_min ON yt.PropertyID = yt_min.PropertyID AND yt.OrderNumber = yt_min.min_order_number

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Erik HauserSenior Technical ConsultantAuthor Commented:
JimHorn,

Thank you so much!  I was practically there in two separate queries and couldn't figure out how to join them.

Thanks, I'll try that!
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LowfatspreadCommented:
;with cte as (select [first inspection date]
                      ,row_number() over ( partition by propertyid order by ordernumber) as rn
    from propertycalcs)
update  x
   set [first inspection date]='first inspection date'
 from cte as x
where rn=1
 and [first inspection date] <> 'first inspection date'
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Scott PletcherSenior DBACommented:
I'd suggest storing just a bit flag that indicated this: you can translate it to the characters using a computed column.

isFirstInspectionDate bit

update ...
set isFirstInspectionDate = 1
...


ALTER TABLE PropertyCalcs
ADD [First Inspection Date] AS CASE WHEN isFirstInspectionDate = 1 THEN 'First Inspection Date' ELSE '' END
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