Re: [sqlite] What does the first expr do in a CASE statement ?

[John LeSueur]

Randall Fox wrote:
What does the first expr do in a CASE expression ?
I understand the rest of the syntax, but I don't get what the very
first expr (after the keyword "case") does..  And I couldn't find the
answer in the documentation or wiki..
Thanks
Randall Fox
 

There's a few ways you can use case statements, I think you're referring 
to this:

select
   case field1
      when 1 then
            field1+1
      when 2 then
            field1/2
      else
            1
   end as casefield
   from table1;
in which case, field1 will be compared to each "when value" to determine 
which "then value" to return.  It's very similar to a switch statement.

Case can also be used as an if elseif else type statement, when the 
field is omitted.

select
   case
      when field1 is null then
         field2
      else
         field1
   end as casefield
   from table1;
John LeSueur