Select Top 1 field and assign to local variable

Question

I want to take the value of ExtractedDate from this query and use it as @LastExtractDate in the next query. How do I do that?

    SELECT TOP 1 [ExtractedDate]     FROM [OnsiteV4].[dbo].[SqlPendingIndex] order by ExtractedDate desc 

next query:

    insert into @table(Hex, KeyDeviceId, ObjectDateTime, ExtractedDate  ) SELECT     CONVERT(VARCHAR(MAX), CONVERT(VARBINARY(MAX), ObjectValue, 1)) AS Hex, KeyDeviceId, ObjectDateTime , GETDATE ()     FROM         SQLPending     WHERE     (ObjectSubType LIKE '%GAS%') and (ObjectDateTime > @LastExtractDate) 

Answer 1

why not use this:

declare @LastExtractDate date SELECT TOP 1 @LastExtractDate=[ExtractedDate] FROM [OnsiteV4].[dbo].[SqlPendingIndex] order by ExtractedDate desc 

Answer 2

Simply declare & assign:

DECLARE @LastExtractDate DATETIME = (     SELECT TOP 1 [ExtractedDate] FROM [OnsiteV4].[dbo].[SqlPendingIndex] order by ExtractedDate desc ) 

or better:

DECLARE @LastExtractDate DATETIME = (     SELECT MAX(ExtractedDate) FROM [OnsiteV4].[dbo].[SqlPendingIndex] )