Create a new column with a query

Question

I have a table full of dates, the dates are unique but for each date I want to have numbers 1-3. So as it stands now all the dates are distinct but my objective is to have a new column where each date has 3 rows instead of one with the numbers 1-3.

Right now my table looks like this:

Date
1/1/2016
2/1/2016

What I want is this:

Date     | Number
1/1/2016 | 1
1/1/2016 | 2
1/1/2016 | 3
2/1/2016 | 1
2/1/2016 | 2
2/1/2016 | 3

Is this possible with a query?

Answer 1

cross join with generate_series .

select d.dt,n.num
from dates_tbl d
cross join generate_series(1,3) n(num)

Answer 2

You could do this in a number of ways.

Here's one:

start by modify the table to add the additional number field. then create a table and insert the values 1, 2, 3 into the table as three different rows. If you only want to do this as a one-off you could do this as a temp table:

CREATE TEMPORARY TABLE temp_location
(
   number int
) 
ON COMMIT DROP;

INSERT into your table with the new field the results of a CROSS JOIN with the numbers table and your dates.