Mysql select - all from left and only matching right table

Question

I have two tables:

1. employees

   [id, first_name, last_name, status]

2. absence

   [id, employee_id, reason_type, date_from, date_to

I can do something like:

SELECT e.first_name, e.last_name, e.status, a.reason_type FROM employees e JOIN absence a ON e.id=a.employee_id
WHERE curdate() between date_from and date_to 

but it will give me only those employees that are found in absence table.

Is there a way to get a list of ALL employees and their status (for those found in absence table matching condition currdate() between date_from and date_to return 'Yes' and reason_type) and for others say No and null for reason_type.

Thanks.

Answer 1

You are looking for a left join, but you have to be careful about the where clause:

SELECT e.first_name, e.last_name, e.status, a.reason_type
FROM employees e LEFT JOIN
     absence a
     ON e.id = a.employee_id AND
        curdate() between a.date_from and a.date_to ;

Answer 2

You want a LEFT JOIN. That does exactly what you want: all values on the left-hand side of the join, and null on the right if there's no match.

There's also (unsurprisingly) a RIGHT JOIN, that does things the other way round.

Answer 3

You can use the below query..

SELECT e.first_name, e.last_name, e.status, a.reason_type 
FROM employees e 
 LEFT JOIN absence a ON e.id=a.employee_id
WHERE curdate() between date_from and date_to