how to create a range of values and then use them to insert data into postgresql database

Question

Background Information:

I need to auto generate a bunch of records in a table. The only piece of information I have is a start range and an end range. Let's say my table looks like this:

     id 
     widgetnumber

The logic needs to be contained within a .sql file.
I'm running postgresql

Code

This is what I have so far... as a test... and it seems to be working:

DO $$
DECLARE widgetnum text;
BEGIN
    SELECT 5 INTO widgetnum;

    INSERT INTO widgets VALUES(DEFAULT, widgetnum);
END $$;

And then to run it, I do this from a command line on my database server:

testbox:/tmp# psql -U myuser -d widgets -f addwidgets.sql 
DO

Questions

1. How would I modify this code to loop through a range of widget numbers and insert them all? for example, I would be provided with a start range and an end range (100 to 150 let's say)

2. Can you point me to a good online resource to learn the syntax i should be using?

Thanks.

Answer 1

How would I modify this code to loop through a range of widget numbers and insert them all?

You can use generate_series() for that.

insert into widgets (widgetnumber)
select i
from generate_series(100, 150) as t(i);

Can you point me to a good online resource to learn the syntax i should be using?

https://www.postgresql.org/docs/current/static/index.html