Generate a table with number sequence in sql

ktnd

Generate a table with number sequence in sql
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1 Pre-defined collection types in Oracle
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select to_number(column_value) as num from   table(sys.dbms_debug_vc2coll(1,2,3,4,5,6,7,8,9));select to_number(column_value) as num from   table(sys.KU$_VCNT(1,2,3,4,5,6,7,8,9));select column_value as num from   table(sys.KU$_OBJNUMSET(1,2,3,4,5,6,7,8,9)); 
2 Join: pure sql
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select a.i+b.i+c.i+d.i+1 as numfrom   (select 0 i from dual union all select 1 from dual) a,   (select 0 i from dual union all select 2 from dual) b,   (select 0 i from dual union all select 4 from dual) c,   (select 0 i from dual union all select 8 from dual) dorder by num; 
 
3 How to make number dynamic?
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?
 
3.1 Define function with collection type as return value
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It's not only sql.
And myaybe it's not correct or appropriate for dynamic.
However, I like it.
 
First, define a type:
 
create or replace type T_NUM_TAB as TABLE OF NUMBER; 
Then, define the function:
 
CREATE OR REPLACE FUNCTION NUM_COLLECT (       NUM_START IN NUMBER,        NUM_END IN NUMBER,       NUM_STEP IN NUMBER DEFAULT 1)  RETURN T_NUM_TABAS  l_tab   T_NUM_TAB := T_NUM_TAB();  l_idx   NUMBER;BEGIN  l_idx := NUM_START;  WHILE l_idx <= NUM_END LOOP    l_tab.extend;    l_tab(l_tab.last) := l_idx;    l_idx := l_idx + NUM_STEP;  END LOOP;  RETURN l_tab;END; 
Now, use it as follows:
 
SQL> select * from table(num_collect(2,10,2));COLUMN_VALUE------------           2           4           6           8          10  Is it a good idea to take sql string as parameter for the function?