[Tutor] Table Joins
Terry Carroll
carroll at tjc.com
Wed Aug 22 18:22:36 CEST 2007
On Wed, 22 Aug 2007, Terry Carroll wrote:
> If you want to pull them out of the database as a single table....
> I was wondering that myself the other day. I was planning on looking
> into whether you could just do a FULL OUTER JOIN (which is essentially a
> union operation) on both tables. I haven't checked that out, yet; you
> might want to look into it.
Actually, I'm making this much too hard (especially as I think SQLite, the
only SQL database I have access to, apparently does not directly support
FULL OUTER JOIN). But I just discovered the UNION keyword on the SELECT
statement:
sqlite> create table a1 (v1 int primary key, v2 text);
sqlite> create table a2 (v1 int primary key, v2 text);
sqlite> insert into a1 values(1, 'a');
sqlite> insert into a1 values(2, 'b');
sqlite> insert into a1 values(3, 'c');
sqlite> insert into a1 values(4, 'd');
sqlite> insert into a1 values(5, 'e');
sqlite> insert into a2 values(1, 'a');
sqlite> insert into a2 values(5, 'e');
sqlite> insert into a2 values(9, 'i');
sqlite> insert into a2 values(15, 'o');
sqlite> insert into a2 values(21, 'u');
sqlite> select * from a1;
1|a
2|b
3|c
4|d
5|e
sqlite> select * from a2;
1|a
5|e
9|i
15|o
21|u
sqlite> select * from a1 union select * from a2;
1|a
2|b
3|c
4|d
5|e
9|i
15|o
21|u
Would that do what the OP wanted? You'd have to make the union select a
Python call, of course.
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