Alternative for Cartesian and Cross Join - sql

Question

I want to output all the possible combination in two tables without using cartesian join or cross join. Is this possible?

Answer 1

I want to output all the possible combination in two tables without using cartesian join or cross join. Is this possible?
By a strict definition level, it is not possible. Why? Because the definition of a Cartesian product is exactly what you describe (the term "Cartesian join" is not often used but is a synonym for "Cartesian product"). Hence, any method that you use is implementing this functionality. Normally this functionality is implementing using CROSS JOIN (and I reluctantly admit, sometimes using ,).
You might say "add 1 to a number without doing + 1". Someone else comes along and says "use + 2 - 1". Well, that is adding one, but just using two operations rather than one.
If you want a Cartesian product but you don't want to use the CROSS JOIN operator, the most typical method uses ON 1=1:
select t1.*, t2.*
from t1 join
t2
on 1 = 1;

Answer 2

All possible combinations is the definition of a cartesian product.
Here are 3 alternatives to get a cartesian product from two tables.
All 3 alternatives eventually boils down to a cross join (and execution plan is the same for all 3):
Create and populate sample tables:
CREATE TABLE t1
(
int_col int
)
CREATE TABLE t2
(
char_col char(1)
)
INSERT INTO t1 VALUES
(1), (2), (3), (4), (5), (6), (7), (8), (9), (10)
INSERT INTO t2 VALUES
('a'), ('b'), ('c'), ('d'), ('e'), ('f'), ('h'), ('i'), ('j'), ('k')
The queries:
An implicit cross join:
SELECT *
FROM t1, t2
An explicit cross join:
SELECT *
FROM t1
CROSS JOIN t2
Cross apply:
SELECT *
FROM t1
CROSS APPLY t2
All results are the same:
int_col char_col
1 a
2 a
3 a
4 a
5 a
6 a
7 a
8 a
9 a
10 a
1 b
2 b
3 b
4 b
5 b
6 b
7 b
8 b
9 b
10 b
1 c
2 c
3 c
4 c
5 c
6 c
7 c
8 c
9 c
10 c
1 d
2 d
3 d
4 d
5 d
6 d
7 d
8 d
9 d
10 d
1 e
2 e
3 e
4 e
5 e
6 e
7 e
8 e
9 e
10 e
1 f
2 f
3 f
4 f
5 f
6 f
7 f
8 f
9 f
10 f
1 h
2 h
3 h
4 h
5 h
6 h
7 h
8 h
9 h
10 h
1 i
2 i
3 i
4 i
5 i
6 i
7 i
8 i
9 i
10 i
1 j
2 j
3 j
4 j
5 j
6 j
7 j
8 j
9 j
10 j
1 k
2 k
3 k
4 k
5 k
6 k
7 k
8 k
9 k
10 k