Question

Looking for best advice on how to do this:

I have an insert like this:

insert into empty_table (
column_1,
column_2,
column_3,
column_4
)
(select
sequence_1.nextval,
v_variable_1,
v_variable_2,
value_1
from template_table
where some_value = "value 1");

The select statement on its own returns 22 records. What I want to do is iterate over this insert and set the variables equal to values from another query like:

select
variable_1,
variable_2
from table_with_var_values
where some_other_value = "value 2";

This query returns about 180 records and looks like this:

variable_1    variable_2
------------------------
Abc           101         
Def           102         
Ghi           103         
Jkl           104
etc...

So the ultimate result will be that empty_table holds 3,960 records (22 x 180) and will look something like this:

column_1    column_2    column_3    column_4
--------------------------------------------
1           Abc         101         Spring
2           Def         102         Summer
3           Ghi         103         Spring
4           Jkl         104         Fall
etc...

I can store this as function in a package but I am unsure how to begin structuring a function like this. Thanks in advance for any help.

Answer 1

Why not just combine the two queries and do your INSERT, as in:

insert into empty_table (column_1,          
                         column_2,          
                         column_3,          
                         column_4)   
  SELECT sequence_1.nextval,  
         t2.variable_1,
         t2.variable_2,
         tt.v_variable_1,  
    from template_table tt,
         table_with_var_values t2
    where tt.some_value = 'value 1' AND
          t2.some_other_value = 'value 2'

Because there’s no join criteria between TEMPLATE_TABLE and TABLE_WITH_VAR_VALUES you should get a Cartesian join, where every row of both tables are joined together, which is what I think you want. No need to loop to get that.

Not sure which of your template_table columns had the ‘Spring’, ‘Summer’, and ‘Fall’ values so I just picked v_variable_1 – substitute as needed.

Share and enjoy.