Country which is NOT in reading

code sender country
(12) Jane France
(12) Jane Spain
(15) Andy Germany
(15) Mary Italy
(16) Tom Spain[/code]I have a table named “sending” like the above and another table named reading like the below.

(read_day) reader country (11) Andy Germany (12) Jane Italy (14) Andy France (16) Tom GermanyWhen I like to find matching country in the table “reading”, I can use the code below.

SELECT as country FROM reading LEFT JOIN sending ON WHERE is NOT null GROUP BY countryThe code above produces the result below.

France Germany ItalySo far so good.

Now I like to find countries which are not in the table “reading”.
I made the trial code below for it.

SELECT as country FROM reading LEFT JOIN sending ON WHERE is null GROUP BY country My target result is the following, but the code above produces nothing.


Why does the trial code above produce nothing?
How can I get my target result above?

because there is no row in reading where the country is null

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Would it need to be something along the lines of

SELECT from reading where not in (select distinct as scountry from sending)

In what table are these countries?

sending, as I read it.

joon has merely forgotten how left joins work and which table is supposed to be on the left

i wonder if there’s a language problem in interpreting our replies/suggestions?

SELECT as country FROM sending LEFT JOIN reading ON WHERE is null GROUP BY countryI’ve got my target result with the code above.

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