number series

Patrick Wolf wrote about the newest Apex release, which contains a 11.2 db engine, so I had to play with recursive queries ;)


with t(x) as (select 1 from dual 
union all
select x+1 from t where x<5 )
select x from t;

X
1
2
3
4
5

with t(x,y) as (select 1 x, 1 y from dual 
union all
select x+1,y*(x+1) from t where x<5 )
select x,y "X!" from t;

X  X!
1  1
2  2
3  6
4  24
5  120

with t(r,x,y) as (select 1,1,1 from dual 
union all
select r+1,y,x+y from t where r<5)
select x fib from t

FIB 
1 
1 
2 
3 
5 

with t1(x) as (select 1 from dual 
union all
select x+1 from t1 where x<4),
t2(x,y,z) as (select x, 1,x from t1
union all 
select x,y+1,x*(y+1) from t2 where y<2)
select listagg(z,';') within group (order by x) s from t2 group by y;

S 
1;2;3;4 
2;4;6;8 

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