SQL query Postgres 12

Question

I'm doing an inner join on a table like this:

SELECT * 
FROM  patient p
INNER JOIN 
    vaccine v
ON 
    p.vaccine_id =  v.id

The condition f.vac_1 = mv.id might not been satisfied in the case where a person have not been vaccinated. In such case, I don't want to ignore the row, but instead of displaying the vaccine name (which is the purpose of the inner join) to display an emtpy string.

How can this be done ?

Example

Table vaccinne

id	name
1	Moderna
2	Comirnaty
3	Janssen

Table patient

id	name	vaccine_id
1	john	1
2	kermit	2
3	jessica

I'm looking for a query to produce:

id	name	vaccine_id
1	john	Moderna
2	kermit	Comirnaty
3	jessica

What row? Sample data and desired results would help.

Gordon Linoff
– Gordon Linoff

2021-06-12 17:08:26 +00:00
Commented Jun 12, 2021 at 17:08 — Gordon Linoff
– Gordon Linoff, Commented Jun 12, 2021 at 17:08
@GordonLinoff Ok, will add now

Hey StackExchange
– Hey StackExchange

2021-06-12 17:09:08 +00:00
Commented Jun 12, 2021 at 17:09 — Hey StackExchange
– Hey StackExchange, Commented Jun 12, 2021 at 17:09

Gordon Linoff · Accepted Answer · 2021-06-12 17:15:32Z

1

If I understand correctly, you want a left join starting with foo:

SELECT * 
FROM foo f LEFT JOIN
     vac v 
     ON f.vac_1 =  mv.id

edited Jun 12, 2021 at 17:15

answered Jun 12, 2021 at 17:08

Gordon Linoff

1.3m62 gold badges705 silver badges857 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Hey StackExchange Over a year ago

Thank you very much, it work. Much appreciated!

Collectives™ on Stack Overflow

SQL query Postgres 12

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related