It will probably work if you remove the AS.
SELECT main_table.field, join_table.field
FROM main_table
LEFT JOIN main_table join_table ON join_table.id = main_table.parent_id
On 6/13/07, Steve Lefevre <lefevre.10@osu.edu> wrote:Hello all -
I'm trying to do a JOIN within a table. In MySQL, I would do
SELECT main_table.field, join_table.field
FROM main_table
LEFT JOIN main_table AS join_table ON join_table.id = main_table.parent_id
Or something like that.
However, in the Postgres documentation, I don't see anything on JOIN AS.
How would I do a join within a table in Postgres?
The table in question is a genetics table of viruses. The columns are
id, strain, and parent_id. Since viruses only replicate, each strain has
one parent. This way I can have one table and show entire tree of the
relationship. It guarantees that I have only one parent per virus.
The only other way I can think of doing it would be to have two tables:
table strains
------------
id
strain
table relationships
--------------
parent_id
child_id
But then I think I would have to implement some constraints so that I
don't get more than one parent per child.
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