All of the documentation for Cosmos DB and it looks like it only supports the JOINkeyword, which seems to be a sort of INNER JOIN.
I have the following query:
SELECT * FROM
(
SELECT
DISTINCT(c.id),
c.OtherCollection,
FROM c
JOIN s IN c.OtherCollection
)
AS c order by c.id
This works fine and returns the data of documents that have OtherCollection populated. But It obviously does not return any documents that do not have it populated.
The reason for the join is that sometimes I execute the following query (queries are built up from user input)
SELECT * FROM
(
SELECT
DISTINCT(c.id),
c.OtherCollection,
FROM c
JOIN s IN c.OtherCollection
WHERE s.PropertyName = 'SomeValue'
)
AS c order by c.id
The question is how can I have a sort of LEFT JOIN operator in this scenario?
CosmosDB JOIN operation is limited to the scope of a single document. What possible is you can join parent object with child objects under same document.
It is totally different from SQL Join query which supports across two/many tables.
You can simulate LEFT JOIN with the EXISTS sentence.
Eg:
SELECT VALUE c
FROM c
WHERE (
(c.OtherCollection = null) OR EXISTS (--Like a "Left Join"
SELECT null
FROM s IN c.OtherCollection
WHERE s.PropertyName = 'SomeValue'
)
)
--AND/OR Some other c Node conditions
order by c.id
Related
i have i would like to create a join over several tables.
table login : I would like to retrieve all the data from login
table logging : calculating the Nb_of_sessions for each db & for each a specific event type by user
table meeting : calculating the Nb_of_meetings for each db & for each user
table live : calculating the Nb_of_live for each db & for each user
I have those queries with the right results :
SELECT db.id,_id as userid,firstname,lastname
FROM "logins"."login",
UNNEST(dbs) AS a1 (db)
SELECT dbid,userid,count(distinct(sessionid)) as no_of_visits,
array_join(array_agg(value.from_url),',') as from_url
FROM "loggings"."logging"
where event='url_event'
group by db.id,userid;
SELECT dbid,userid AS userid,count(*) as nb_interviews,
array_join(array_agg(interviewer),',') as interviewer
FROM "meetings"."meeting"
group by dbid,userid;
SELECT dbid,r1.user._id AS userid,count(_id) as nb_chat
FROM "lives"."live",
UNNEST(users) AS r1 (user)
group by dbid,r1.user._id;
But when i begin to try put it all together, it seems i retrieve bad data (i have only on db retrieved) and it seems not efficient.
select a1.db.id,a._id as userid,a.firstname,a.lastname,count(rl._id) as nb_chat
FROM
"logins"."login" a,
"loggings"."logging" b,
"meetings"."meeting" c,
"lives"."live" d,
UNNEST(dbs) AS a1 (db),
UNNEST(users) AS r1 (user)
where a._id = b.userid AND a._id = c.userid AND a._id = r1.user._id
group by 1,2,3,4
Do you have an idea ?
Regards.
The easiest way is to work with with to structure the subquery and then reference them.
with parameter reference:
You can use WITH to flatten nested queries, or to simplify subqueries.
The WITH clause precedes the SELECT list in a query and defines one or
more subqueries for use within the SELECT query.
Each subquery defines a temporary table, similar to a view definition,
which you can reference in the FROM clause. The tables are used only
when the query runs.
Since you already have working sub queries, the following should work:
with logins as
(
SELECT db.id,_id as userid,firstname,lastname
FROM "logins"."login",
UNNEST(dbs) AS a1 (db)
)
,visits as
(
SELECT dbid,userid,count(distinct(sessionid)) as no_of_visits,
array_join(array_agg(value.from_url),',') as from_url
FROM "loggings"."logging"
where event='url_event'
group by db.id,userid
)
,meetings as
(
SELECT dbid,userid AS userid,count(*) as nb_interviews,
array_join(array_agg(interviewer),',') as interviewer
FROM "meetings"."meeting"
group by dbid,userid
)
,chats as
(
SELECT dbid,r1.user._id AS userid,count(_id) as nb_chat
FROM "lives"."live",
UNNEST(users) AS r1 (user)
group by dbid,r1.user._id
)
select *
from logins l
left join visits v
on l.dbid = v.dbid
and l.userid = v.userid
left join meetings m
on l.dbid = m.dbid
and l.userid = m.userid
left join chats c
on l.dbid = c.dbid
and l.userid = c.userid;
Can somebody help me in converting below mentioned query in to Maximo's where clause:
select distinct workorder.wonum from workorder inner join [assignment]
On workorder.wonum=[assignment].wonum
inner join amcrew
On amcrew.amcrew=[assignment].amcrew
inner join amcrewlabor
On amcrewlabor.amcrew=amcrew.amcrew
inner join labor
On amcrewlabor.laborcode=labor.laborcode
inner join person
on labor.laborcode=person.personid where amcrewlabor.laborcode='KELLYB'
KELLYB is PERSONID used here for just reference.
If you are using a custom search query in Maximo, you can try prepending your with in (your query)
For example, if you're in Maximo's work order tracking module, the application uses select * from workorder by default. Any time you add a search filter such as work order number (wonum), then the query appends to run a query as select * from workorder where wonum = '123' if 123 is the work order number you entered.
Your where clause might look something like this:
wonum in (
select distinct workorder.wonum
from workorder
join assignment on workorder.wonum=assignment.wonum
join amcrew on amcrew.amcrew=assignment.amcrew
join amcrewlabor on amcrewlabor.amcrew=amcrew.amcrew
join labor on amcrewlabor.laborcode=labor.laborcode
join person on labor.laborcode=person.personid
where amcrewlabor.laborcode='KELLYB'
)
The SQL that is generated in Microsoft Access will not necessarily work in Maximo without some modification.
I'm fairly new to SQL and have started running into sub-queries as in this query below:
SELECT C.CustomerID
, C.Name
, ( Select PhoneNumber
FROM PhoneNumberTable P
WHERE P.CustomerID = C.CustomerID ) AS "PhoneNumber"
FROM CustomerTable C
Comparing to this query with a join below:
SELECT C.CustomerID
, C.Name
, P.PhoneNumber
FROM CustomerTable C
JOIN PhoneNumberTable P
ON P.customerID = C.customerID
Is there a difference in terms of efficiency/speed? The SQL I am working with has several sub-queries as I have shown above (no JOINs) and it is difficult to read.
joins in my experience tend to be faster, but sometimes you need a subquery.
you should also look into CTE they are very usefull and much easier (in my opinion) to manage
in your specific case i would use a join... because you are trying to join the 2 tables together.
I'm using Hive 0.9.0 and I'm trying to execute query i.e.
`SELECT a.id, b.user FROM (SELECT...FROM a_table) a, (SELECT...FROM b_table) b WHERE a.date = b.date;`
but it returns error "loop (...)+ does not match input....".
Does Hive support multiple subqueries in FROM just like Oracle DB?
Multiple subqueries allowed in hive.
I tested with below code,it works.
select * from (select id from test where id>10) a
join (select id from test where id>20) b on a.id=b.id;
Please post your exact code so that I can give relevant solution.
join subqueries is supported Absolutely.
I think the key problem is that u use SELECT...FROM.
The correct syntax is SELECT * FROM
SELECT a.id, b.user
FROM
(SELECT * FROM a_table) a
JOIN (SELECT * FROM b_table) b ON a.date = b.date;
If you want to obtain the full Cartesian product before applying the WHERE
clause, instead:
SELECT a.id, b.user FROM (SELECT...FROM a_table) a, (SELECT...FROM b_table) b WHERE a.date = b.date;
you should use 'join' in the middle, i.e.
SELECT a.id, b.user FROM (SELECT...FROM a_table) a join (SELECT...FROM b_table) b WHERE a.date = b.date;
above is not admissible in strict mode.
How to change this complex sql statement into JPQL?
select a.name, a.surname, b.street, c.location, c.location_desc
from table1 join table2 on b.id = a.some_fk
left join table3 d on d.id = a.id
left join table4 c on c.some2_id = d.some2_fk where a.id = 400;
If this is possible to present in the JPQL form?
Impossible to give a definitive answer without knowing the entities and their mapping, but the query would look like this:
select a.name, a.surname, b.street, c.location, c.locationDesc
from Entity1 a
join a.entity2 b
left join a.entity3 d
left join d.entity4 c
where a.id = 400;
provided the necessary associations between entities are there.
JPQL is object oriented, it operates against JPA entity objects ,not database tables. Either you need to change the Question and add an UML diagramm or provide the Entity classes.