Re: SQL SELECT: controlling the order of evaluation

You want to only return 1 record, with priority given to a match on zip, then city, etc.?

Maybe something like

select {}
     , case when zip=33166 then 1
            when city = 'MIAMI' then 2
            when county = 'DADE' then 3
            when state = 'FL' then 4
            else 9
        end Priority
   from {}
 where state='FL'
    or county='DADE'
    or city='MIAMI'
    or postal='33166'
 order by priority
 fetch first row only


On 2/2/2023 12:25 PM, x y wrote:

When I have multiple conditions on my WHERE clause, can I control the order
in which they're evaluated?

Example: the client in postal code 33166, Miami, Dade County, Florida, is
looking for a local resource. I'd like to write
select {} from {} where state='FL' or county='DADE' or city='MIAMI' or
postal='33166' fetch first row only
and then tell SQL to return a result by evaluating first on postal, then
city, then county, and then state.

I'm trying to avoid multiple SELECT statements. It's impractical to add
"helper" data in the table, which will have > 100 million records. Putting
"postal='33166'" first doesn't provide the desired result. A UNION ALL
won't work. I don't think a JOIN will work but I'm trying to figure out
how it might work.

It looks like SQL selects the first row that meets any of the selection
criteria, i.e., SQL is giving all the conditions equal weight). I'm using
CASE in my ORDER BY for other requirements but I can't figure out if that's
the solution here.

Thanks for your ideas!

--x