How can I translate a script I wrote in SQL server to compute the odds ratios to Postgresql?

问题

In SQL server, I wrote the following script to calculate the odds ratios based the probabilities of my test group divided by my control group. The script is as follows:

--Compute the odds ratios from the model  
select a.column1, a.uvs as testuvs. b.uvs as controluvs
       , [odds]=case when b.uvs>0 then a.puvs/b.puvs else Null end 
into unique_visitor_odds 
from control_probabilties b
    inner join test_probabilities a
    on a.column1=b.column2
 where a.uvs>24 and b.uvs>24 
 order by [odds] desc

I am not sure how to write this in Postgresql.

回答1:

The code is remarkably similar:

create table unique_visitor_odds as
    select tp.column1, tp.uvs as testuvs, cp.uvs as controluvs,
           tp.puvs / nullif(cp.puvs, 0) as odds
    from control_probabilties cp inner join
         test_probabilities tp
         on tp.column1 = cp.column2
    where cp.uvs > 24 and tp.uvs > 24 
    order by odds desc ;

I removed the case statement in the select. That is handled by the where. Postgres is smart enough to respect the where when reporting errors. And, you can prevent a divide by zero by using nullif().

Except fro the create table as and into clauses, the same code works in both databases.

Also, the order by is suspicious. I'm actually surprised the SQL Server allows it.

回答2:

Besides the potential type between your second and third column in the SELECT clause and the oddball alias syntax, everything should translate to postgres easily:

SELECT a.column1,
    a.uvs AS testuvs,
    b.uvs AS controluvs,
    CASE WHEN b.uvs > 0 THEN a.puvs / b.puvs ELSE NULL END AS odds
INTO unique_visitor_odds
FROM control_probabilties b
INNER JOIN test_probabilities a ON a.column1 = b.column2
WHERE a.uvs > 24 AND b.uvs > 24
ORDER BY odds DESC

来源：https://stackoverflow.com/questions/43480456/how-can-i-translate-a-script-i-wrote-in-sql-server-to-compute-the-odds-ratios-to

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sql

postgresql

data-analysis