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
623 views
in Technique[技术] by (71.8m points)

sql - Simple recursive query in Oracle

I'm currently having some trouble understanding and writing recursive queries. I understand that recursive queries are used to search through hierarchies of information, but I haven't found a simple solution online that can travel up a hierarchy. For example, let's say that I have a relation that models a family tree:

create table family_tree (
child varchar(10)
parent varchar(10)
);

If I wanted to write a recursive query that travelled up this family tree, collecting all parents until origin, how should I go about this?

Thanks in advance.

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)

You can use connect by clause.

In your case, SQL might look like:

select child, parent, level
from family_tree 
connect by prior parent = child

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

...