Joining tbl1 to select statement twice with join to tbl2 that also joins to tbl3 - sql

I'm using SQL server manger.
I have 3 tables
I need a query that pulls t1 ands add an Origin Basin and a Destination Basin.
So far I have the following:
select T1.[Country (destination)], T3.AreaName
From T1
left outer join T2 on
T1.[Country (destination)] = T2.CountryName
inner join T3 on
T2.AreaID = T3.AreaID
inner join T3 on
T2.AreaID = T3.AreaID
Which returns:
Country | Area
However, I'm having trouble doing this for the second country column. I believe you use aliases. I've tried:
select (select AreaName
FROM T3
where T3.AreaID = T2.AreaID) as 'Area Imp',
(select AreaID
From T2
where T2.CountryName = T1.[Country (origin)]) as 'x',
(select AreaID
From T2
where T2.CountryName = T1.[Country (destination)]) as 'y'
FROM T1
But I can't get it to work.


This is what you need to do:
select t1.date, t1.country_destination, t1.country_origin, destination_area.AreaName as area_destination, origin_area.AreaName as area_origin
from t1 as t1 join t2 as destination on t1.country_destination = destination.countryname
join t2 as origin on t1.country_origin = origin.countryname
join t3 as destination_area on t2.areaid = destination_area.areaid
join t3 as origin_area on t2.areaid = origin_area.areaid
You will need to join with the same table twice, both for t2 and t3 so that you get the matching records for your needs.
It helps usually to put aliases that match the purpose of the join (in this case, destination and origin) when writing the query.


I think what you're trying to do is something like this:
select T1.*, T3dest.AreaName, T3orig.AreaName
From
T1
inner join
T2 T2dest on
T1.[Country (destination)] = T2dest.CountryName
inner join
T3 T3dest on
T2dest.AreaID = T3dest.AreaID
inner join
T2 T2orig on
T1.[Country (origin)] = T2orig.CountryName
inner join
T3 T3orig on
T2orig.AreaID = T3orig.AreaID
Note that I've switched to inner joins throughout, at the moment. If you do want left join semantics, you either need to use those for all of the joins to the T2 and T3 tables or you need to change the join order (so that the relevant T3 joins to the T2 tables occur before the attempted join with T1). It's not clear from the sample data if that's required, however.


Try this, You would still want to join on area id's
select T1.Date,T1.[Country (destination)], null [Country (origin)], T3.AreaName [AreaName(Destination)], null [AreaName(Origin)]
From T1
left outer join T2 on
T1.[Country (destination)] = T2.CountryName
inner join T3 on
T2.AreaID = T3.AreaID
union all
select T1.Date,null [Country (destination)], t1.[Country (origin)], Null [AreaName(Destination)], t3. [AreaName(Origin)]
From T1
left outer join T2 on
T1.[Country (Origin)] = T2.CountryName
inner join T3 on
T2.AreaID = T3.AreaID

Related

multiple inner joins in bigquery result in duplicated rows

Im tryin to join 6 tables in bigquery named
T0, T1, T2, T3, T4, T5
The tables result im interested are T0 and T1
after query this tables I got 43 matches
SELECT
T1.F1,
T0.F2,
T0.F3,
T0.F4,
T1.F5,
T1.F6,
T1.F7,
T1.F8
T0.F9
FROM `TABLE0` T0
INNER JOIN `TABLE1` T1 on T1.F1= T0.F1
WHERE T0.F1 = "010001476713"
AND T0.F2 = T1.F2
ORDER BY T0.F4
But when I run this with multiple INNER JOIN I got 800 results not the 43, results are duplicated
SELECT
T2.F11,
T3.F15,
T2.F12,
T3.F16,
T3.F17,
T1.F1,
T2.F13,
T3.F17,
T5.F18,
T5.F19,
T5.F20,
T2.F14,
T0.F9,
T1.F10,
T4.F3,
T4.F21,
T4.F22,
T0.F2,
T3.F23,
T0.F3,
T0.F4,
T1.F5,
T1.F6,
T1.F7,
T1.F8
FROM `TABLE0` T0
INNER JOIN `TABLE1` T1 ON T1.F1= T0.F1
INNER JOIN `TABLE3` T3 ON T3.F1=T1.F1
INNER JOIN `TABLE2` T2 ON T2.F24 = T3.F24
INNER JOIN `TABLE4` T4 ON T4.F3 = T0.F3
INNER JOIN `TABLE5` as T5 ON T5.F1=T0.F1
WHERE T0.F1 = "010001476713"
AND T0.F2 = T1.F2
ORDER BY T0.F4

When I get duplicate rows, I solve it like this:
You get 43 results on your inner join of table T0 & T1. So far so good.
Now comment out everything related to table T2, T4, & T5 (I've placed the commas at the beginning of the row for easier commenting out) like this
SELECT
--T2.F11,
T3.F15
--,T2.F12
,T3.F16
,T3.F17
,T1.F1
--,T2.F13
,T3.F17
--,T5.F18
--,T5.F19
--,T5.F20
--,T2.F14
,T0.F9
,T1.F10
--,T4.F3
--,T4.F21
--,T4.F22
,T0.F2
,T3.F23
,T0.F3
,T0.F4
,T1.F5
,T1.F6
,T1.F7
,T1.F8
FROM `TABLE0` T0
INNER JOIN `TABLE1` T1 ON T1.F1= T0.F1 and T0.F2 = T1.F2
INNER JOIN `TABLE3` T3 ON T3.F1=T1.F1
--INNER JOIN `TABLE2` T2 ON T2.F24 = T3.F24
--INNER JOIN `TABLE4` T4 ON T4.F3 = T0.F3
--INNER JOIN `TABLE5` as T5 ON T5.F1=T0.F1
WHERE T0.F1 = "010001476713"
ORDER BY T0.F4
I've moved the and T0.F2 = T1.F2 from the where to on in the inner join. When you run this query, do you still get 43 rows, or more? If more, you need to figure out what it is double matching on, and add that to your on statement of it really is a 1-1 relationship, or perhaps group the results if you don't want multiple matches. You may need to comment out your select statement and select all to really figure it out, like this:
SELECT *
/*
--T2.F11,
T3.F15
--,T2.F12
,T3.F16
,T3.F17
,T1.F1
--,T2.F13
,T3.F17
--,T5.F18
--,T5.F19
--,T5.F20
--,T2.F14
,T0.F9
,T1.F10
--,T4.F3
--,T4.F21
--,T4.F22
,T0.F2
,T3.F23
,T0.F3
,T0.F4
,T1.F5
,T1.F6
,T1.F7
,T1.F8
*/
FROM `TABLE0` T0
INNER JOIN `TABLE1` T1 ON T1.F1= T0.F1 and T0.F2 = T1.F2
INNER JOIN `TABLE3` T3 ON T3.F1=T1.F1
--INNER JOIN `TABLE2` T2 ON T2.F24 = T3.F24
--INNER JOIN `TABLE4` T4 ON T4.F3 = T0.F3
--INNER JOIN `TABLE5` as T5 ON T5.F1=T0.F1
WHERE T0.F1 = "010001476713"
ORDER BY T0.F4
Once you figure out what rows are causing the duplication, you either group the results or add an 'and' statement to the on clause to make it a 1-1, and then move on. You then uncomment the parts of the query related to T2 and do the same thing, then T4 and then T5. If you send me the results of the query above, I can help you figure out what your on clause needs to be to keep it from duplicating.

thank you #jenstretman, I find table 4 to be duplicating matches by using a foreign Key with non-primary Key creating duplicates, the solution was to use a DISTINCT to only select specifically matched rows.
SELECT DISTINCT
T2.F11,
T3.F15,
T2.F12,
T3.F16,
T3.F17,
T1.F1,
T2.F13,
T3.F17,
T5.F18,
T5.F19,
T5.F20,
T2.F14,
T0.F9,
T1.F10,
T4.F3,
T4.F21,
T4.F22,
T0.F2,
T3.F23,
T0.F3,
T0.F4,
T1.F5,
T1.F6,
T1.F7,
T1.F8
FROM `TABLE0` T0
INNER JOIN `TABLE1` T1 ON T1.F1= T0.F1
INNER JOIN `TABLE3` T3 ON T3.F1=T1.F1
INNER JOIN `TABLE2` T2 ON T2.F24 = T3.F24
INNER JOIN (SELECT DISTINCT T4.F3, T4.F21, T4.F22, FROM `TABLE4` T4)T4 ON T4.F3 = T0.F3
INNER JOIN `TABLE5` as T5 ON T5.F1=T0.F1
WHERE T0.F1 = "010001476713"
AND T0.F2 = T1.F2
ORDER BY T0.F4

Combine column after left join

How do I combine 3 returned value columns into one column based on which column is not null?
My query is:
SELECT val1,val2,val3
FROM db.table1 t1
LEFT JOIN db.table2 t2 ON t2.pk = t1.t2_fk
LEFT JOIN db.table3 t3 ON t3.pk = t1.t3_fk

use coalesce()
SELECT coalesce(val1,val2,val3) as va
FROM db.table1 t1
left join db.table2 t2
on t2.pk = t1.t2_fk
left join db.table3 t3
on t3.pk = t1.t3_fk

How to replace an OR statement from a join in sql server

I have the following query that uses an or statement on a join, so basically if one condition on the join isn't met it must check the next condition. The problem is that with the OR statement it takes really long to run but when I remove one of the OR conditions it runs instantly. is there a better way to do this with both conditions without using the OR statement so it would speed up the query
select t5.TransactionNumber
,t4.ID
,t3.[Entry] AS Amount
,t2.Address AS AddressDetail
,t1.PhoneNumber AS ContactNumber
FROM Table1 t1 (NOLOCK)
JOIN Table2 t2 (NOLOCK) ON t2.FicaID = t1.FicaId
inner join Table3 t3 (NOLOCK) ON (t3.ID = t2.ID AND t3.Code = t2.Code) or (t3.TypeID = t2.TypeID) //on this join i have an or statement if one condition isnt met it must check the next condition
LEFT JOIN Table4 t4 (NOLOCK) ON t4.Result = t3.Result
LEFT JOIN Table5 t5 (NOLOCK) ON t5.AccNum = t3.AccNum
where t1.date>'2018-09-01' and t1.date<'2018-09-30'

By the rule of distributivity in logic,
P OR (Q AND R) can be written as
(P OR Q) AND (P OR R).. maybe that helps?

You could try by using left join and COALESCE function
select t5.TransactionNumber
,t4.ID
,COALESCE(t3.[Entry],t33.[Entry]) AS Amount
,t2.Address AS AddressDetail
,t1.PhoneNumber AS ContactNumber
FROM Table1 t1 (NOLOCK)
JOIN Table2 t2 (NOLOCK) ON t2.FicaID = t1.FicaId
left join Table3 t3 (NOLOCK) ON (t3.ID = t2.ID AND t3.Code = t2.Code)
left join Table3 t33 (t33.TypeID = t2.TypeID) //I moved it to left join
LEFT JOIN Table4 t4 (NOLOCK) ON t4.Result = t3.Result
LEFT JOIN Table5 t5 (NOLOCK) ON t5.AccNum = t3.AccNum
where t1.date>'2018-09-01' and t1.date<'2018-09-30'

You can try below query :
select * from
(
select t5.TransactionNumber
,t4.ID
,t3.[Entry] AS Amount
,t2.Address AS AddressDetail
,t1.PhoneNumber AS ContactNumber
FROM Table1 t1 (NOLOCK)
JOIN Table2 t2 (NOLOCK) ON t2.FicaID = t1.FicaId
inner join Table3 t3 (NOLOCK) ON (t3.ID = t2.ID AND t3.Code = t2.Code)
)A
join Table3 t3 (NOLOCK) ON (A.TypeID = t3.TypeID)
LEFT JOIN Table4 t4 (NOLOCK) ON t4.Result = t3.Result
LEFT JOIN Table5 t5 (NOLOCK) ON t5.AccNum = t3.AccNum
where t1.date>'2018-09-01' and t1.date<'2018-09-30'

How do I get the results of one JOIN and THEN feed those into a separate join in T-SQL?

I'm trying to JOIN 2 tables ON a key like
SELECT column1,column2
FROM Table1 t1
INNER JOIN Table2 t2 ON t1.t2id = t2.id
Now, I have a 3rd table that has a Foreign Key with t2's id that I want to join... When I do
LEFT JOIN
Table3 t3 ON t3.t2id = --<-------------- This is where I'm lost
I don't know if I should do ON t3.t2id = t1.t2id OR ON t3.t2id = t2.id
What I need is the list of t2ids which are still in the picture after the first join. However, it seems as though if I specify either of the above, it will just pull ids from the original table before the first join?
To clarify one more time: I'm trying to essentially do a INNER JOIN of Table1 and Table2, get the resulting table, then get the t2ids of those results and feed them into a final join such that the final result contains all of Table3's rows as well as the data from the first join

You said: "final result contains all of Table3's rows as well as the data from the first join".
It means that you need
Table3 LEFT JOIN <previous results>
instead of
<previous results> LEFT JOIN Table3
The easiest way to write it is to use Common-Table Expressions:
WITH
CTE_InnerJoin
AS
(
SELECT column1, column2, t1.t2id
FROM
Table1 t1
INNER JOIN Table2 t2 ON t1.t2id = t2.id
)
SELECT
CTE_InnerJoin.column1
,CTE_InnerJoin.column2
,Table3....
FROM
Table3
LEFT JOIN CTE_InnerJoin ON CTE_InnerJoin.t2id = Table3.t2id
;
It doesn't matter what column you include in the CTE: t1.t2id or t2.id, the values in them are the same, because they are inner-joined together.

JOINs already do exactly what you want. A JOIN isn't always between two tables. Frequently, it's between the results of previous joins.
SELECT column1,column2
FROM Table1 t1
INNER JOIN Table2 t2 ON t1.t2id = t2.id
LEFT JOIN
Table3 t3 ON t3.t2id = t2.id
At the point at which you're writing the final ON clause here, what you're joining is precisely the results of the previous INNER JOIN on the left and the table Table3 on the right. All of t1, t2 and t3 are in scope within the ON clause, but note that t1 and t2 are now both used as aliases into the same source of rows - the previous INNER JOIN.
As a further example, consider the "diamond join":
SELECT
*
FROM
t1
left join
t2
on
t1.a = t2.b
left join
t3
on
t1.c = t3.d
inner join
t4
on
t2.e = t4.f OR
t3.g = t4.h
This is a way of joining two tables (t1 and t4) based on two alternative joins. Note that in the final inner join, what is on the "left" is the result of already joining tables t1, t2 and t3.

Join the table having foreign key with
Try this....
SELECT column1,column2
FROM Table1 t1
INNER JOIN Table2 t2 ON t1.t2id = t2.id
LEFT join Table3 t3 ON t2.id=t3.t2id

Or Like this.
SELECT t12.column1 ,
t12.column2 ,
t3.*
FROM (
--- INNER JOIN of Table1 and Table2, get the resulting table,
SELECT t1.column1 ,
t2.column2 ,
t1.t2id --- or t2.id doesn't matter because its inner join
FROM Table1 t1
INNER JOIN Table2 t2 ON t1.t2id = t2.id
) T12
LEFT JOIN Table3 T3 ON t3.t2id = t1.t2id --- then get the t2ids of those results
--- and feed them into a final join
--- if you want to get all rows from Table3, Change LEFT JOIN Table3 T3 ON t3.t2id = T1.t2id
--- into RIGHT JOIN Table3 T3 ON t3.t2id = T1.t2id

try this
select t3.*, column1, column2
from
table1 t1 inner join table2 t2 on t1.t2id = t2.id
right outer join table3 t3 on t3.t2id = t2.id
equvalent to
select t3.*, column1, column2
from
table1 t1 inner join table2 t2 on t1.t2id = t2.id
right outer join table3 t3 on t3.t2id = t1.t2id

if you want all rows from table 3 and those matching rows from table1 inner joined to table2 then you can use this syntax:
select t3.*,
column1, column2
from table3 t3
left join table2 t2
inner join table1 t1
on t1.t2id = t2.id
on t3.t2id = t2.id

Joining multiple tables by skipping On condition for few tables and join them alone

I want to understand how we can join by skipping the On condition. Let me explain with example. If you notice in below query, there is no ON condition for T3 and I am just joining with that table to T4 table.
Question: How Data set will create and how that will combine to other other data set?
SELECT * FROM T1
INNER JOIN T2 ON T1.ID = T2.ID
INNER JOIN T3
LEFT JOIN T4 ON T3.ID = T4.ID
LEFT JOIN T5 ON T1.ID = T5.ID

Well, when there is no join relation, then you are basically performing a CROSS JOIN , your query is basically equivalent to :
SELECT * FROM T1
INNER JOIN T2 ON T1.ID = T2.ID
CROSS JOIN(SELECT * FROM T3
LEFT JOIN T4 ON T3.ID = T4.ID)
LEFT JOIN T5 ON T1.ID = T5.ID