I have come across some hql that looks like this:
select a.id
from something a inner join a.whatever b,
somethingelse c inner join c.blah d
where a.id = c.id
Why is a inner joined to b and c inner joined to d but a is linked to c via where
What exactly is this hql saying? Please explain in simple terms.
This query means that the a and b are related in the model. Same is the case with c and d.
In order to join a and c, you have to explicitly state the join field, i.e., id since the model does not have this information.
Related
I have a below query
How to use full outer join for TABLE T4 for getting all records?
WHERE
(DB.T4.AUTH_REV_NO=DB.T2.AUTH_REV_NO
AND DB.T4.AUTH_NO=DB.T2.AUTH_NO)
AND (DB.T2.AUTH_CURR_IN='Y' )
AND (DB.T3.AUTH_NO=DB.T2.AUTH_NO)
AND (DB.T3.AUTH_REV_NO=DB.T2.AUTH_REV_NO )
AND (DB.T6.FNC_ID=DB.T4.FNC_ID)
AND (DB.T7.FNC_SEG_ID=DB.T6.FNC_SEG_ID)
AND (DB.T1.SCT_ID(+)=DB.T7.SCT_ID
AND DB.T1.FNC_SEG_ID(+)=DB.T7.FNC_SEG_ID)
AND (DB.T8.NDE_ID=DB.T12.NDE_ID)
AND (DB.T7.FNC_SEG_ID=DB.T8.FNC_SEG_ID)
AND (DB.T7.SCT_ID=DB.T8.SCT_ID)
AND ((DB.T12.NDE_ID=DB.T6.NDE_STRT_ID)
OR (DB.T12.NDE_ID=DB.T6.NDE_END_ID))
AND (DB.T5.FNC_ID(+)=DB.T4.FNC_ID)
AND (T13_A4.REF_ID(+)=DB.T5.REF_TONE_TYP_ID)
AND (fne.FNC_SEG_ID=DB.T8.FNC_SEG_ID)
AND (fne.NDE_ID=DB.T8.NDE_ID)
AND (fne.SCT_ID=DB.T8.SCT_ID)
AND fnode.NDE_ID=DB.T6.NDE_STRT_ID
AND tnode.NDE_ID=DB.T6.NDE_END_ID
AND (DB.T4.REF_FNC_TYP_ID=T13_A1.REF_ID)
AND (ne_port.NDE_EQP_ID=fne.NDE_EQP_ID)
AND (ne_port.NDE_EQP_PRN_ID=ne_card.NDE_EQP_ID)
AND (ne_card.NDE_EQP_PRN_ID=ne_shelf.NDE_EQP_ID)
AND (ne_shelf.NDE_EQP_PRN_ID=ne_rack.NDE_EQP_ID)
AND (eq.EQP_ID=ne_card.EQP_ID)
AND (eq.REF_EQP_CLS_ID=T13_A2.REF_ID)
AND (DB.T3.REF_AUTH_STS_ID=T13_A3.REF_ID)
AND (DB.T3.AUTH_STS_ID
IN (SELECT MAX(DB.T3.AUTH_STS_ID) FROMDB.T3
WHERE (DB.T3.AUTH_NO,DB.T3.AUTH_REV_NO)
IN
(SELECT
DB.T3.AUTH_NO,
MAX(DB.T3.AUTH_REV_NO)
FROM
DB.T3
GROUP BY
DB.T3.AUTH_NO)
GROUP BY
DB.T3.AUTH_NO))
How to use full outer join for TABLE T4 and for COLUMN FNC_TONE_LVL_QT to get all records.
Please help.
You posted a whole lot of "joins". I'm not going to rewrite it for you, but - I'd suggest you to switch to a more recent explicit JOIN syntax which makes things somewhat simpler and easier to understand as you'd separate joins from conditions. Moreover, it allows you to outer join the same table to more than just one another table, which is impossible with the old (+) Oracle's outer join operator.
Something like this
select ...
from table_1 a left join table_2 b on a.id = b.id
full outer join table_3 c on c.id = a.id
...
I'm trying to find all entries in table a, where there is no matching entry in table b for one specific column (order). I'm using the following:
SELECT *
FROM a
LEFT OUTER JOIN b
ON a.id = b.id
WHERE b.order IS NULL
AND a.result>10
However, the last condition for result doesn't seems to work. It simply lists all the entries from table a, regardless whether result is more than 10 or not.
Any way around this?
Shouldn't your query be as below?
SELECT * FROM a LEFT OUTER JOIN b ON a.id = b.id WHERE b.id IS NULL AND a.result>10
I have two tables A and B that both have a column id. I wish to obtain ids from A that are not present in B. The obvious way is:
SELECT id FROM A WHERE id NOT IN (SELECT id FROM B)
Unfortunately, Hive doesn't support in, exists or subqueries. Is there a way to achieve the above using joins?
I thought of the following
SELECT A.id FROM A,B WHERE A.id<>B.id
But it seems like this will return the entirety of A, since there always exists an id in B that is not equal to any id in A.
You can do the same with a LEFT OUTER JOIN in Hive:
SELECT A.id
FROM A
LEFT OUTER JOIN B
ON (B.id = A.id)
WHERE B.id IS null
Hive seems to support IN, NOT IN, EXIST and NOT EXISTS from 0.13.
select count(*)
from flight a
where not exists(select b.tailnum from plane b where b.tailnum = a.tailnum);
The subqueries in EXIST and NOT EXISTS should have correlated predicates (like b.tailnum = a.tailnum in above sample)
For more, refer Hive Wiki > Subqueries in the WHERE Clause
Should you ever want to do an IN as so:
SELECT id FROM A WHERE id IN (SELECT id FROM B)
Hive has this covered with a LEFT SEMI JOIN:
SELECT a.key, a.val
FROM a LEFT SEMI JOIN b on (a.key = b.key)
if you can using spark sql you can use left anti join.
ex: SELECT A.id FROM A left anti join B on a.id=b.id
I have three tables A B and C. Now i want to execute this sql query in HQL:
select * from A as a
left join
B as b
on
a.id = b.id
left join
C as c
on
b.type=c.type;
Need help in writing equivalent HQL. I tried with this HQL...
Query q = session.createQuery(
"FROM A as a
LEFT JOIN
B as b
on
a.id=b.id
LEFT JOIN
C as c
on
b.type=c.type");
This query is throwing exception .....
org.hibernate.hql.ast.QuerySyntaxError: unexpected token: LEFT near
line 1, column 23 [FROM com.admin.A as a LEFT JOIN B as b where
a.Id=b.Id LEFT JOIN C as c where b.type=c.type] at
org.hibernate.hql.ast.ErrorCounter.throwQueryException(ErrorCounter.java:74)
at
org.hibernate.hql.ast.QueryTranslatorImpl.parse(QueryTranslatorImpl.java:214)
at
org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:127)
at
org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:83)
at
org.hibernate.impl.SessionFactoryImpl.getQuery(SessionFactoryImpl.java:414)
I also tried with "with" and "on" clauses instead of where...I get the same unexpected token on "on" or "with"
exception qith ON .....
org.hibernate.hql.ast.QuerySyntaxError: unexpected token: ON near line
1, column 41 [FROM com.admin.A as a LEFT JOIN B as b on a.Id=b.Id LEFT
JOIN C as c onb.type=c.type] at
org.hibernate.hql.ast.ErrorCounter.throwQueryException(ErrorCounter.java:74)
at
org.hibernate.hql.ast.QueryTranslatorImpl.parse(QueryTranslatorImpl.java:214)
at
org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:127)
at
org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:83)
at
org.hibernate.impl.SessionFactoryImpl.getQuery(SessionFactoryImpl.java:414)
I also tried with "with" clauses instead of where...I get the same unexpected token on or "with"
exception qith WITH .....
org.hibernate.hql.ast.QuerySyntaxError: unexpected token: ON near line
1, column 41 [FROM com.admin.A as a LEFT JOIN B as b on a.Id=b.Id LEFT
JOIN C as c onb.type=c.type] at
org.hibernate.hql.ast.ErrorCounter.throwQueryException(ErrorCounter.java:74)
at
org.hibernate.hql.ast.QueryTranslatorImpl.parse(QueryTranslatorImpl.java:214)
at
org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:127)
at
org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:83)
at
org.hibernate.impl.SessionFactoryImpl.getQuery(SessionFactoryImpl.java:414)
Please help.
I suppose you've already defined all the needed associations in your configuration. If so, in HQL it would look like this:
from A as a left join a.B as b left join b.C as c
There is no "ON" statement in HQL, hibernate does automatically based on your mappings and defined Associations.
Pay attention to a.B and b.C.
You refer to B and C based on already defined aliases a & c.
Use this query
from A as a
left join fetch a.B as b
left join fetch b.C as c
Dim ds = From a In db.Model
Join b In db.1 On a.id Equals b.ID
Join c In db.2 On a.id Equals c.ID
Join d In db.3 On a.id Equals d.ID
Join f In db.4 On a.id Equals f.ID
Select a.id, a.Ref, a.Type, a.etc
Above is my linq query. At the moment I am only getting the first row from the db returned when there are currently 60 rows. Please can you tell me where I am going wrong and how to select all records.
Thanks in advance!
UPDATE:
When I take out all the joins like so:
Dim ds = From a In db.1, b In db.2, c In db.3, d In db.4, f In db.5
Select a.id, a.Ref, a.type, b.etc, c.etc, d.etc
I get a system.outofmemory exception!
You're only going to get a row produced when all of the joins match - in other words, when there's a row from Model with an AP, an Option, a Talk and an Invoice. My guess is that there's only one of those.
LINQ does an inner join by default. If you're looking for a left outer join (i.e. where a particular row may not have an Invoice, or a Talk etc) then you need to use a group join, usually in conjunction with DefaultIfEmpty.
I'm not particularly hot on VB syntax, but this article looks like it's what you're after.