A>По какой-то загадочной причине приоритет унарных плюса и минуса сделан в Transact-SQL таким же, как и у бинарных, т. е. ниже чем у умножения и деления. Это поведение задокументировано.

это старый баг с 7 версии. каждые пару лет очередной дев его обнаруживает

2005 год
2008 год

ответ парня из мс (2005 год):

Thank you for the report. This is a known bug that was found very late in the product cycle. At the time, we couldn't think of any repros where it would affect anything other than rounding at the time, but obviously we missed this one. Because of the late date and the requirement for difficult compat work to fix this in the current product but maintain the old behavior in compat mode, we decided to postpone it. I agree that it needs to be fixed since the behavior is very unintuitive, but the fix would be a breaking change that's not suitable for a service pack. It's unfortunate and very surprising to everyone who stumbles across it, but it's actually been this way since 7.0. This is on the radar and will hopefully be fix early in Katmai development.

Jerry
jweiler@microsoft.com
SQL Server Engine Development