SQL select return 0 if no records found, else return value

Question

I am now using Microsoft SQL, my code is:

   SELECT TOP 1 
   [avail]
   FROM [table1]
   where [name] = \'abc\'
   order by [datetime] desc

I

Answer 1

If its top 1 you want or remove top command

 SELECT TOP 1 
   isnull([avail],'0')
   FROM [table1]
   where [name] = 'abc'
   order by [datetime] desc