generate_series

hi,

the following behaviour of multiple generate_series in a select seems
a little counter-intuitive to me.  i expected that the former returns 4 rows.
where should i look to learn the exact semantics?  (documentation and/or code)

YAMAMOTO Takashi

test=# select generate_series(1,2) as a,generate_series(1,2) as b;
 a | b
---+---
 1 | 1
 2 | 2
(2 rows)

test=# select generate_series(1,2) as a,generate_series(1,3) as b;
 a | b
---+---
 1 | 1
 2 | 2
 1 | 3
 2 | 1
 1 | 2
 2 | 3
(6 rows)