Update Volume using query in SQL

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Update Volume using query in SQL

caojunhe24

Ten Centuries

Points: 1334
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September 24, 2018 at 7:40 am

#408544

hi experts,
I have one simple question here about update the value using query itself as shown below.
is there a simple way to update Volume column using query column?
first 4 rows will return same value,
thanks
Austin

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caojunhe24 Ten Centuries Points: 1334 More actions · Answer 1

Im thinking add seq number to the table and using seq to update each row in the table but am not sure. any suggestion?

declare @seq int =1

declare @seq_max int = (select max(seq) from [AdventureWorksDW2008R2].[dbo].[test])

declare @sql varchar(max)= (select query from [AdventureWorksDW2008R2].[dbo].[test] where seq = @seq)

while (@seq <= @seq_max)

update a

set a.volume = ??????

from [AdventureWorksDW2008R2].[dbo].[test]a

where seq = @seq

@seq =@seq +1

ChrisM@Work SSC Guru Points: 186127 More actions · Answer 2

caojunhe24 - Monday, September 24, 2018 7:40 AM
hi experts,
I have one simple question here about update the value using query itself as shown below.
is there a simple way to update Volume column using query column?
first 4 rows will return same value,
thanks
Austin

Please define exactly what content you want in the [volume] column and how it's derived.

^{“Write the query the simplest way. If through testing it becomes clear that the performance is inadequate, consider alternative query forms.” - Gail Shaw}

For fast, accurate and documented assistance in answering your questions, please read this article.
Understanding and using APPLY, (I) and (II) Paul White
Hidden RBAR: Triangular Joins / The "Numbers" or "Tally" Table: What it is and how it replaces a loop Jeff Moden

caojunhe24 Ten Centuries Points: 1334 More actions · Answer 3

Hi guru,

the volume should be float value and it's derived from query column{select count(*) from ..}

e.g in the first row if you excute the select query from [query] column it will have 20 this 20 should be in [Volume] column.

thanks
Austin