Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
1.0k views
in Technique[技术] by (71.8m points)

postgresql - Matching algorithm in SQL

I have the following table in my database.

# select * FROM matches;
 name | prop |  rank
------+------+-------
 carl |    1 |     4
 carl |    2 |     3
 carl |    3 |     9
 alex |    1 |     8
 alex |    2 |     5
 alex |    3 |     6
 alex |    3 |     8
 alex |    2 |    11
 anna |    3 |     8
 anna |    3 |    13
 anna |    2 |    14
(11 rows)

Each person is ranked at work by different properties/criterias called 'prop' and the performance is called 'rank'. The table contains multiple values of (name, prop) as the example shows. I want to get the best candidate following from some requirements. E.g. I need a candidate that have (prop=1 AND rank > 5) and (prop=3 AND rank >= 8). Then we must be able to sort the candidates by their rankings to get the best candidate.

EDIT: Each person must fulfill ALL requirements

How can I do this in SQL?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)
select x.name, max(x.rank) 
from matches x
join (
    select name from matches where prop = 1 AND rank > 5
    intersect
    select name from matches where prop = 3 AND rank >= 8
) y
    on x.name = y.name 
group by x.name
order by max(rank);

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...