Translate MYSQL query to HQL using multiple JOINS - mysql

Question

everyone.
I am using grails 3.3.0.M2 framework with mysql as data-source the following sql query is working as expected
SELECT
c.name,
SUM(CASE
WHEN t.status = 'open' THEN 1
ELSE 0
END) 'open',
SUM(CASE
WHEN t.status = 'pending' THEN 1
ELSE 0
END) 'in progress',
SUM(CASE
WHEN t.status = 'closed' THEN 1
ELSE 0
END) 'closed'
FROM
tickets t
INNER JOIN
users u ON t.user_id = u.id
INNER JOIN
user_coordinations uc ON uc.user_id = u.id
INNER JOIN
coordinations c ON c.id = uc.coordination_id
GROUP BY 1
I translated to HQL using implicit JOIN but I am getting the wrong results, here is the hql query:
SELECT
c.name,
SUM(CASE
WHEN t.status = 'open' THEN 1
ELSE 0
END),
SUM(CASE
WHEN t.status = 'pending' THEN 1
ELSE 0
END),
SUM(CASE
WHEN t.status = 'closed' THEN 1
ELSE 0
END)
FROM
Ticket t, User u, UserCoordination uc, Coordination c
WHERE
MONTH(t.dateCreated) = :month
GROUP BY 1
In order to get the right results stack overflow users help me to understand that the query needs to use explicit JOINS, here the question: Group by a field that does not belongs to the consulted table
Right now I am trying with the following query:
SELECT
c.name,
SUM(CASE
WHEN t.status = 'open' THEN 1
ELSE 0
END),
SUM(CASE
WHEN t.status = 'pending' THEN 1
ELSE 0
END),
SUM(CASE
WHEN t.status = 'closed' THEN 1
ELSE 0
END)
FROM
Ticket t
INNER JOIN
User u
INNER JOIN
UserCoordination uc
INNER JOIN
Coordination c
WHERE
MONTH(t.dateCreated) = :month
GROUP BY 1
But i am getting a com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException with the caused message You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'inner join user_coordinations usercoordi2_ on inner join coordinations coordinat' at line 1
Thanks for your help and time

Answer 1

SELECT new map(
c.name as name,
(CASE
WHEN t.status = 'open' THEN 1
ELSE 0
END) as open,
(CASE
WHEN t.status = 'pending' THEN 1
ELSE 0
END) as pending,
(CASE
WHEN t.status = 'closed' THEN 1
ELSE 0
END) as closed,
SUM(open) as openSum,
SUM(pending) as pendingSum,
SUM(closed) as closedSum
)
FROM
Ticket t
left join t.user u left join u.userCoordination uc left join uc.coordination c
WHERE
MONTH(t.dateCreated) = :month
//GROUP BY 1
What you had had lots missing above is more like what you need, you need
select new map(i.item as item... if you compare the basics of this with what you had and what i tried to do you can see why you had errors.
unsure about your group by it should be group by something. Wasn't sure by inner join if you just meant a join if that was the case leave out all the left join since left join attempts to connect and get any null hasMany relations etc.