列含糊不清的错误

Question

i have this code

select people_id,first_name 
FROM people , PUBAUTHOR_PEOPLE 
WHERE people.people_id = PUBAUTHOR_PEOPLE. people_id 

and it says column ambigously defined does anybody know why and how to fix that?

Answer 1

You should add table name before your coulmn names as below

select people.people_id,people.first_name 
FROM people , PUBAUTHOR_PEOPLE 
WHERE people.people_id = PUBAUTHOR_PEOPLE. people_id 

I recommended you to use aliases as below to make code more readable

select p.people_id,p.first_name 
FROM people p, PUBAUTHOR_PEOPLE pp
WHERE p.people_id = pp.people_id 

I also recommended you to use joins as below

select p.people_id,p.first_name 
FROM people p
join PUBAUTHOR_PEOPLE pp on p.people_id = pp.people_id

It is more readable now, isn't it?

Answer 2

It's complaining because both tables have a column called 'people_id', so you have to specify which table to read it from (even though it will be the same because of the join condition), so something like:

SELECT      people.people_id,
            first_name 

FROM        people, PUBAUTHOR_PEOPLE 

WHERE       people.people_id = PUBAUTHOR_PEOPLE.people_id