Question

I need to write a script to insert data selected from one table into another. The old table stores a value ‘Yes’ in one column but I want to insert 1 instead of ‘Yes’

Is there any way to do this. In my head this is what I want to do:

insert into new_table (new_col1, new_col2)
values (select from old_table(old_col1, (if old_col2='Yes' then 1 else 0))

Answer 1

First: if you base your insert on a SELECT, the must not use the VALUES clause.

To get a conditional value, use the (ANSI standard) CASE statement:

insert into new_table (new_col1, new_col2)
select old_col1, 
       case 
         when old_col2 = 'Yes' then 1 
         else 0 
       end
from old_table

An Oracle only more compact form would be the decode() statement (but I’d recommend to use the CASE, because it’s more readable and portable to other DBMS as well)

insert into new_table (new_col1, new_col2)
select old_col1, 
       decode(old_col2, 'Yes', 1, 0)
from old_table