mysql sqlserver下更新多表的区别

mysql 下:

update VideoFrequency , VideoFrequencyLibrary
set VideoFrequency. resourceUrl = VideoFrequencyLibrary.Url

where
?VideoFrequency.id = VideoFrequencyLibrary.videoId
and
length(resourceUrl) < 1

sqlserver下:

?

update VideoFrequency
set VideoFrequency. resourceUrl = VideoFrequencyLibrary.Url
from? VideoFrequency, VideoFrequencyLibrary
where
?VideoFrequency.id = VideoFrequencyLibrary.videoId
and
length(resourceUrl) < 1

?

?

?

?