expression: return null when cast to huge binary type (#8768)#9350

Merged

jackysp merged 2 commits intopingcap:release-2.0from eurekaka:cast_binary_20

Feb 19, 2019

+68-18

Commits on Feb 18, 2019

expression: return null when cast to huge binary type (pingcap#8768 )
eurekaka
committed

Commits on Feb 19, 2019

tiny fix
eurekaka
committed