Hi!
I expect the SELECT to return two rows. Would some kind
soul explain for me why it gives only one row?
TIA
CN
=============
CREATE TABLE x(c1 text,c2 int2);
INSERT INTO x VALUES('a',10);
INSERT INTO x VALUES('b',NULL);
CREATE TABLE y(c1 int2,c2 int2,c3 text);
INSERT INTO y VALUES(10,9,'yyy');
CREATE TABLE z(c1 text,c2 text);
INSERT INTO z VALUES('a','zzz');
INSERT INTO z VALUES('b','zzzz');
SELECT x.c1,y.c3,z.c2
FROM x JOIN z USING (c1)
LEFT OUTER JOIN y ON (x.c2=y.c1)
WHERE y.c2=9;
c1 | c3 | c2
----+-----+-----
a | yyy | zzz
=========================
Comment: The following version of SELECT does return two
rows as expected, however:
SELECT x.c1,y.c3,z.c2
FROM x JOIN z USING (c1)
LEFT OUTER JOIN y ON (x.c2=y.c1);
c1 | c3 | c2
----+-----+------
a | yyy | zzz
b | | zzzz
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