sql resultset order defined?

Say I've employee table where any employee can be related to any other employee (many to many). Each employee has many characteristics that are stored separately.

emp: id,name
related: name,emp1role,emp1id,emp2role,emp2id
chars: empid,name,value

I want to get all the characteristics of employees who are related via 'xxx' along with the relation. I am currently using this query:

SELECT c.empid, c.Name, c.Value
FROM chars as c, related as r
WHERE r.name='xxx' AND (r.emp1id=c.empid OR r.emp2id=c.empid)

This works and it gives related employees one after another i.e. if emp22 & emp43 are related via 'xxx' then I am getting chars of emp43 followed by emp22 a开发者_如何学Cnd so on. This way I am able to know which two employees are related (which is needed). However, I want to know if this order is mere luck or is it well-defined. This is in SQLite.

If it is not defined way, how else can I do it? Also, I need to know their respective roles. I want to preferably do it in one query. Can you think of some other query?

Thanks in advance,

Manish

PS: These are not actual tables. They are here for simplicity of asking question.

In SQL, ordering of the result is undefined unless you have an explicit ORDER BY clause in your query. So I believe you want:

SELECT c.empid, c.Name, c.Value
FROM chars as c, related as r
WHERE r.name='xxx' AND (r.emp1id=c.empid OR r.emp2id=c.empid)
ORDER BY c.empid ASC

I tend to add a unique field (such as a primary key) at the end, to if not get an obvious ordering when there are multiple records matching in all other order fields, at least get deterministic ordering. But that's largely a matter of style and choice; it's by no means required.