How to make SELECT in this case? [duplicate] - sql-server

Question

This question already has answers here:
Simplifying a query with a nested query
(3 answers)
Closed 1 year ago.
How to create a single MSSQL SELECT query in this case:
We've got 2 tables: fruits and expiration
The goal is to receive table where specific fruit number has information about having NULL in expirationDate column. Those fruit numbers that don't have NULL would have zeros in that column. Number 4 doesn't exist in expiration table, so it would also have 0 in results, because it doesn't have NULL.
Tables

Answer 1

You can't easily get the expiration date on the format you want. However, it does not really matter(?). I assume you want 1 or 0 in your new table because you want to use an if statement to check if the fruit is bad or not.
You can solve this easily:
if(expirationDate == null){/*something*/}
or, you might even be able to do
if(expirationDate) //this is all fruit that is not bad
else{/*your code to deal with expirated fruit here*/}
Note: I don't know what programming languages you are using. But in most of them: null and 0 are FALSE.
if(null) // false
if(0) //false
if(undefined) //false, in javascript
//everything that is not a false value, is true.
if("oiaehgtaoiwgneawg") //true
if(-1) //true
To answer your SQL query question:
You already have everything you need in the expiration table
SELECT fruit_number, expiration_date
FROM expiration;
I hope this helps 😊

Answer 2

You have to use it with Case Condition. But have to change statement a little:
select fruit_number, --distinct(fruit_number),
x =case expiration_date
when NULL then null
else 0
end

Answer 3

My friend found the solution.
SELECT
fruit_number,
MAX(expirationDate) as expirationDate
FROM
(SELECT
f.fruit_number,
CASE
WHEN e.expiration_date is NULL AND e.fruit_number IS NOT NULL THEN 1
ELSE 0
END AS expirationDate
FROM
expiration as e
FULL OUTER JOIN fruits as f ON f.fruit_number = e.fruit_number
WHERE
f.fruit_number IS NOT NULL
) t
GROUP BY
fruit_number
ORDER BY
fruit_number