这句执行的结果,Hits还是null,请问正确的写法？

Question

UPDATE News SET Hits=(CASE Hits WHEN NULL THEN 1 ELSE Hits+1 END) WHERE ID=1

Answer 1

UPDATE NewsSET Hits=(CASE WHEN Hits IS NULL THEN 1 ELSE Hits+1 END)WHERE ID=1

Answer 2

SQL里面的null判断必须写为is nullUPDATE News SET Hits=(CASEWHEN Hits IS NULL THEN 1 ELSE Hits + 1 END)WHERE ID=1

Answer 3

不用case，用isnull函数即可update News set Hits = IsNull( Hits, 0 ) + 1 where ID = 1