I know I am doing something wrong, but both tables appear as joins.
This is my code:
SELECT
*
FROM
table1
LEFT OUTER JOIN
users ON users.id = (SELECT id
FROM table2
WHERE type = 'user') t t.id
If I had to a join on the other hand site, its feasible and doable, but for this type, I am not sure I can assign the value like this or not
I don't know if I totally understand the query, but if you are looking to use a join table to connect a many to many relationship try this:
SELECT *
FROM table1 t1
LEFT OUTER JOIN table2 on t1.id = t2.id AND t2.type = 'user'
LEFT OUTER JOIN users u on u.id = t2.id
Related
I set the THEATRES size using THEATRES.NUMOFROWS, THEATRES.NUMOFCOLS and each SEAT.SEATNO is tied to THEATRES.ID and SHOWTIMES.ID is tied to THEATRES.ID and TICKET_ITEMS are tied to SHOWTIMES.ID
I want to display all the values by joining the table using where clause for showtime.id. I know outer join will display null on non-matching but my query only shows one records.
SELECT
SHOWTIMES.ID AS SHOWTIMESID,
SHOWTIMES.THEATREID,
THEATRES.THEATRENAME,
THEATRES.NUMOFROWS,
THEATRES.NUMOFCOLS,
SEAT.SEATNO AS SEATLABEL,
SEAT.ROWID,
SEAT.COLUMNID,
TICKET_ITEMS.SEATNO,
TICKET_ITEMS.TICKETCODE
FROM
SHOWTIMES FULL OUTER JOIN TICKET_ITEMS ON SHOWTIMES.ID =TICKET_ITEMS.SHOWTIMESID
FULL OUTER JOIN THEATRES ON SHOWTIMES.THEATREID = THEATRES.ID
FULL OUTER JOIN SEAT ON SEAT.SEATNO = TICKET_ITEMS.SEATNO
WHERE
SHOWTIMES.ID = 1
;
If you are using any kind of OUTER JOIN and you refer to a column in the WHERE you need to handle NULLs. If you don't, you turn the JOIN into an implicit INNER JOIN. Take this simple example:
WITH T1 AS(
SELECT ID, SomeString
FROM (VALUES(1,'abc'),(2,'def')) V(ID, SomeString)),
T2 AS(
SELECT ID, fID, AnotherString
FROM (VALUES(1,1,'asd'),(2,1,'asdased')) V(ID, fID, AnotherString))
SELECT *
FROM T1
LEFT JOIN T2 ON T1.ID = T2.ID
WHERE T2.AnotherString = 'asd';
You might expect to get 2 rows here, one for where T1.ID is 1 with a joined row and 1 for T1.ID is 2, but with no joined rows. That isn't the case due to the WHERE. The correct solution here would be to move the WHERE to the ON:
WITH T1 AS(
SELECT ID, SomeString
FROM (VALUES(1,'abc'),(2,'def')) V(ID, SomeString)),
T2 AS(
SELECT ID, fID, AnotherString
FROM (VALUES(1,1,'asd'),(2,1,'asdased')) V(ID, fID, AnotherString))
SELECT *
FROM T1
LEFT JOIN T2 ON T1.ID = T2.ID
AND T2.AnotherString = 'asd';
With what you have, you can't do that, as you're using the base table, thus you'll need handle the NULL by changing your WHERE to:
WHERE SHOWTIMES.ID = 1 OR SHOWTIMES.ID IS NULL;
I imagine that your database has proper foreign key relationships set up -- so the theater id in one table is a valid id.
If so, you don't need full join. In fact, it is very rarely needed. I suspect that inner joins are sufficient (but that is the results you are getting).
If you want all theaters with the appropriate shows -- if any -- then use left join and start with the theaters:
select st.ID AS SHOWTIMESID, st.THEATREID,
th.THEATRENAME, th.NUMOFROWS, th.NUMOFCOLS,
s.SEATNO AS SEATLABEL, s.ROWID, s.COLUMNID,
ti.SEATNO, ti.TICKETCODE
from theatres th left join
showtimes st
on st.theatreid = th.id and st.id = 1 left join
ticket_items ti
on st.ID =ti.showtimesid left join
seat s
on s.seatno = ti.seatno
I've got 3 tables that I want to join and filter on some conditions.
I've first wrote this query:
select * from table1 t1
left join (select * from table2 where table2.fieldX=...) t2
on t1.id_12=t2.id_12
left join table3
on t2.id_23=t3.id_23
where t1.fieldY=...
Then I wanted to make it looks like more canonical by rewritting it like that:
select * from table1 t1
left join table2 t2
on t1.id_12=t2.id_12
left join table3
on t2.id_23=t3.id_23
where table2.fieldX=...
and t1.fieldY=...
But it does not give the same result.
I dont't understand why...
Do you?
Thanks in advance.
When you put table2.fieldX=... in the where clause you eliminate all rows from table1 that do not have a corresponding row in table2. Effectively you are changing the left join into an inner join.
Instead, you can apply the table2 filter in the join itself:
SELECT
*
FROM
Table1 t1
LEFT JOIN Table2 t2 ON t1.id_12 = t2.id_12 AND t2.fieldX = ...
LEFT JOIN Table3 t3 ON t2.id_23 = t3.id_23
WHERE
t1.fieldY = ...
Did you add the inner select where on the second query?
SELECT *
FROM table1 t1
LEFT JOIN table2 t2
on t1.id_12=t2.id_12
LEFT JOIN table3
on t2.id_23=t3.id_23
WHERE t1.fieldY=...
and t2.fieldX=...
I was given a query that uses some very weird syntax for a join and I need to understand how this join is being used:
SELECT
T1.Acct#
, T2.New_Acct#
, T3.Pool#
FROM DB.dbo.ACCT_TABLE T1
LEFT JOIN DB.dbo.CROSSREF_TABLE T2
INNER JOIN DB.dbo.POOL_TABLE T3
ON T2.Pool# = T3.Pool#
ON T1.Acct# = T2.Prev_Acct#
T1 is a distinct account list
T2 is a distinct account list for each Pool #
T3 is a distinct pool list (group of accounts)
I need to return the previous account number held in T2 for each record in T1. I also need the T3 Pool# returned for each pool.
What I'm trying to understand is why someone would write the code this way. It doesn't make sense to me.
A little indenting will show you better what was intended
SELECT
T1.Acct#
, T2.New_Acct#
, T3.Pool#
FROM DB.dbo.ACCT_TABLE T1
LEFT JOIN DB.dbo.CROSSREF_TABLE T2
INNER JOIN DB.dbo.POOL_TABLE T3
ON T2.Pool# = T3.Pool#
ON T1.Acct# = T2.Prev_Acct#
This is a valid syntax that forces the join order a bit. Basically it is asksing for only the records in table T2 that are also in table T3 and then left joining them to T1. I don't like it personally as it is confusing for maintenance. I would prefer a derived table as I find those much clearer and much easier to change when I need to do maintenance six months later:
SELECT
T1.Acct#
, T2.New_Acct#
, T3.Pool#
FROM DB.dbo.ACCT_TABLE T1
LEFT JOIN (select T2.New_Acct#, T3.Pool#
FROM DB.dbo.CROSSREF_TABLE T2
INNER JOIN DB.dbo.POOL_TABLE T3
ON T2.Pool# = T3.Pool#) T4
ON T1.Acct# = T4.Prev_Acct#
An OUTER APPLY would be clearer here:
SELECT
T1.Acct#,
T4.New_Acct#,
T4.Pool#
FROM DB.dbo.ACCT_TABLE T1
OUTER APPLY
(
SELECT
T2.New_Acct#,
T3.Pool#
FROM DB.dbo.CROSSREF_TABLE T2
INNER JOIN DB.dbo.POOL_TABLE T3 ON T2.Pool# = T3.Pool#
WHERE T1.Acct# = T4.Prev_Acct#
) T4
I have the following sql statement. I am pulling data from a flat tree structure where i want to select a single follower matching abos_daten.erstellt = (select MAX(erstellt)...
The problem is in order to select the correct MAX(erstellt) I need the following condition where t2.parent_id = t1.parent_id. Unfortunatly t1 can't be bound because it referes to the outer select statement. It seems to create a circle.
select * from trees as t1 inner join abos_daten as starter on t1.parent_id = starter.abonr
right outer join
(select * from trees as t3 inner join abos_daten on t3.child_id = abos_daten.abonr
where abos_daten.erstellt = (select MAX(erstellt) from abos_daten inner join trees as t2 on t2.child_id = abos_daten.abonr
where t2.parent_id = t1.parent_id and abos_daten.status_id <> 147
)
) as follower on t1.child_id = follower.abonr
Does anybody know how to solve this? Kind regards,
jonatan
To start with, t1 doesn't actually refer to the outer select statement; it refers to another entity in the from clause. As it happens, SQL server has a syntax that specifically allows this kind of functionality: cross apply/outer apply. To use this in you situation, you'd want something like this (untested since I can't re-create your tables):
select *
from trees as t1
inner join abos_daten as starter
on t1.parent_id = starter.abonr
outer apply (select MAX(erstellt) as max_erstellt
from abos_daten
inner join trees as t2
on t2.child_id = abos_daten.abonr
where t2.parent_id = t1.parent_id
and abos_daten.status_id <> 14) as t_m
right outer join (select *
from trees as t3
inner join abos_daten
on t3.child_id = abos_daten.abonr) as follower
on t1.child_id = follower.abonr
and t_m.max_erstellt = follower.erstellt
How I can join this queries to single select (without temp table)?
SELECT t2.value,
t1.value
FROM table0 t1
INNER JOIN table1 t3 on t1.idrelation = t3.id and t3.idparent=#id
INNER JOIN table2 t2 on t2.idversion = t3.idchild and t2.name = 'FOO'
ORDER BY t1.value
SELECT SELECT COALESCE(t4._NAME+','+'')
FROM table1 t1
JOIN table1 t2 on t2.idparent = t1.idchild
JOIN table1 t3 on t3.idparent = t2.idchild
JOIN table3 t4 on t4._ID = t3.idchild
WHERE t1.idparent = #id
AND t4._TYPE ='TXT_CAT'
Something like this would help (once you can tell the columns on which you want to join):
select *
from
(
QUERY 1
) q1
join
(
QUERY 2
) q2
on q1.key1 = q2.key2
If you want to join them, there has to be common or uncommon ground.
Putting the 2 selects together is the easy part when you join the resultant sets, but unless you want all permutations of Ans1 and Ans2, then it is wise to determine some sort of where clause to allow it to be more effecient, and narrow it down for you.
If you give more table information, We could be able to adjust and give you something further, but that is the best we can do without taking arbitrary guesses as to what you are trying to accomplish here.
One thing i can part unto you:
Select A.name, B.id from (Select A.name, A.date from A) join (Select B.id, B.date from B) on A.date = B.date;