A Microsoft extension to the ANSI SQL language that includes procedural programming, local variables, and various support functions.
It seems possible to identify an approximate relation between date and SecondValueA. Check an example:
declare @date as datetime2 = cast('2021-03-29 14:12:37.163' as datetime2)
declare @secondValueA bigint
declare @x1 datetime2 = cast('2021-03-29 14:10:07.159' as datetime2)
declare @x2 datetime2 = cast('2021-03-29 14:15:37.162' as datetime2)
declare @y1 bigint = cast(-232845330 as bigint)
declare @y2 bigint = cast(-1227785454 as bigint) + cast(0x100000000 as bigint)
set @secondValueA = @y1 + (@y2 - @y1) * datediff_big(mcs, @x1, @date) / datediff_big(mcs, @x1, @x2)
if @secondValueA > 0x7FFFFFFF set @secondValueA -= cast(0x100000000 as bigint)
select @date as [date], @secondValueA as SecondValueA