How to “expand” a SQL join such that each unique value in column A “get” all the unique values for B?
I have a dataset with two columns: id and date. The dates are monthly and span from Mar-21 to Aug-21. I am sure this question could be applied to non-date values, but I think dates are more intuitive for this example.
And I want this
id | date | ----+--------+-- a | Mar-21 | a | Apr-21 | a | Aug-21 | <---- 'a' is missing Jun-21 and Jul-21 b | Mar-21 | b | May-21 | <---- 'b' is missing Apr-21 b | Jun-21 | b | Jul-21 | b | Aug-21 |
Basically I want to say “I want every single
id | date | ----+--------+-- a | Mar-21 | a | Apr-21 | a | May-21 | a | Jun-21 | <---- 'a' gets Jun-21 a | Aug-21 | <---- ...and now Jul-21 b | Mar-21 | b | Apr-21 | <---- 'b' gets Apr-21 b | May-21 | b | Jun-21 | b | Jul-21 | b | Aug-21 |
idto get all unique values of