I am struggeling with a left join on a Raima database. I'd like to add an additional join condition, but in this case the join behaves like an inner join, thus I am losing some of the expected results.
Example:
TABLE_A
ID
-------
1
2
3
4
.
TABLE_B
A_ID | B
--------
1 | 1
2 | 1
2 | 2
3 | 2
Query
select * from TABLE_A left join TABLE_B
on TABLE_A.ID = TABLE_B.A_ID
and TABLE_B.B = 1
I am expecting the following result:
1 1 1
2 2 1
3 null null
4 null null
E.g. on an Oracle 11g I get the expected result, but on the Raima it shows me only the first two results. What is the problem here and how to fix it?
You need this
select * from A left join
(select * from B where B=1) bd
on A.ID = bd.A_ID
The query you gave will not give you expected result in oracle also. This will.
PS: Please use different names for table and column
Related
I have 2 tables , one stores IDs and another logs for each ID , i would like to get sum of log for each ID and ID number from these 2 tables
A B
------- -------------
ID ID_C LOG
1 1 15
2 1 30
3 4 44
4 2 14
5 3 88
3 10
2 10
for getting sum query is
SELECT SUM(LOG) FROM B WHERE ID_C ='2' ;
notice ID and ID_C are same but name is different in tables
and for getting all ids available query is
SELECT ID FROM A ;
I would like to get the following table result
result
--------------------
ID SUM
1 45
4 44
2 24
3 98
I tried
SELECT SUM(LOG) FROM B WHERE ID_C in (SELECT ID FROM A ) ;
but it result in sum of all IDs
It looks like you just need a join aggregation here:
SELECT a.ID, SUM(b.LOG) AS SUM
FROM A a
INNER JOIN B b
ON b.ID_C = a.ID
GROUP BY a.ID
ORDER BY a.ID;
Note that the inner join will also remove ID values from the A table which no entries whatsoever in the B table, which seems to be the behavior you want.
you should use inner join and GROUP BY:
SELECT A.ID as ID, SUM(LOG) AS SumLOG
FROM A inner join B ON A.ID = B.ID_C
GROUP BY A.ID
if you needed can use where for ID filter.
I am trying to understand how to create a query to filter out some results based on an inner join.
Consider the following data:
formulation_batch
-----
id project_id name
1 1 F1.1
2 1 F1.2
3 1 F1.3
4 1 F1.all
formulation_batch_component
-----
id formulation_batch_id component_id
1 1 1
2 2 2
3 3 3
4 4 1
5 4 2
6 4 3
7 4 4
I would like to select all formulation_batch records with a project_id of 1, and has a formulation_batch_component with a component_id of 1 or 2. So I run the following query:
SELECT formulation_batch.*
FROM formulation_batch
INNER JOIN formulation_batch_component
ON formulation_batch.id = formulation_batch_component.formulation_batch_id
WHERE formulation_batch.project_id = 1
AND ((formulation_batch_component.component_id = 2
OR formulation_batch_component.component_id = 1 ))
However, this returns a duplicate entry:
1;"F1.1"
2;"F1.2"
4;"F1.all"
4;"F1.all"
Is there a way to modify this query so that I only get back the unique formulation_batch records which match the criteria?
EG:
1;"F1.1"
2;"F1.2"
4;"F1.all"
Thanks for your time!
In this case it is possible to apply the distinct before the join possibly making it more performant:
select fb.*
from
formulation_batch fb
inner join
(
select distinct formulationbatch_id
from formulation_batch_component
where component_id in (1, 2)
) fbc on fb.id = fbc.formulationbatch_id
where fb.project_id = 1
Notice how to use alias for the table names to make the query clearer. Also then in operator is very handy. The use of double quotes with those identifiers is not necessary.
One way would be to use distinct:
SELECT distinct "formulation_batch".*
FROM "formulation_batch"
INNER JOIN "formulation_batch_component"
ON "formulation_batch"."id" = "formulation_batch_component"."formulationBatch_id"
WHERE "formulation_batch"."project_id" = 1
AND (("formulation_batch_component"."component_id" = 2
OR "formulation_batch_component"."component_id" = 1 ))
I know the question asks how to prevent duplicates with inner join but could use an IN clause in the predicate.
SELECT "formulation_batch".*
FROM "formulation_batch" fb
ON "formulation_batch"."id" = "formulation_batch_component"."formulationBatch_id"
WHERE "formulation_batch"."project_id" = 1
AND fb.id IN (SELECT "formulation_batch"."id"
FROM formulation_batch_component
WHERE (("formulation_batch_component"."component_id" = 2
OR "formulation_batch_component"."component_id" = 1 ))
I would like to know what's the logic for multiple joins (for example below)
SELECT * FROM B returns 100 rows
SELECT B.* FROM B LEFT JOIN C ON B.ID = C.ID returns 120 rows
As I know using left join will returns any matching data from the left table which is B if data are found for both table. But how come when using left join, it returns more data than table B itself?
What am I do wrong or misunderstood here? Any guidance are very appreciated. Thanks in advance.
Let be table B:
id
----
1
2
3
Let be table C
id name
------------
1 John
2 Mary
2 Anne
3 Stef
Any id from b is matched with ids from c, then id=2 will be matched twice. So a left join on id will return 4 rows even if base table B has 3 rows.
Now look at a more evil example:
Table B
id
----
1
2
2
3
4
table C
id name
------------
1 John
2 Mary
2 Anne
3 Stef
Every id from b is matched with ids from c, then first id=2 will be matched twice and second id=2 will be matched twice so the result of
select b.id, c.name
from b left join c on (b.id = c.id)
will be
id name
------------
1 John
2 Mary
2 Mary
2 Anne
2 Anne
3 Stef
4 (null)
The id=4 is not matched but appears in the result because is a left join.
Look at the following example :
B = {1,2}
C = {(1,a),(1,b),(1,c),(1,d),(1,e)}
The result of B left join C will be :
1 | a
1 | b
1 | c
1 | d
1 | e
2 | null
The number of rows in the result is definitely larger than rows in B (2).
In general the number of rows in result of B left join C is bounded by B.size + C.size and not only by B.size as you think...
As per your query it do the join to B Table with C and B table is Left Table so it will display all the records of Left table in our case it is B and related from other Table in our Case it is C.
id address retailer
1 A 11
2 A 11
3 A 11
4 A 12
5 A 13
6 B 12
7 B 12
8 B 13
My output should be
id address retailer
1 A 11
4 A 12
5 A 13
6 B 12
8 B 13
i.e my query should return id's which have same address but not same retailer.
How toget this?
Try to use group by clause as below:
select min(id), address, retailer
from tab
group by address, retailer
Assuming you're joining on columns with no duplicates, which is by far the most common case:
An inner join of A and B gives the result of A intersect B, i.e. the inner part of a venn diagram intersection.
An outer join of A and B gives the results of A union B, i.e. the outer parts of a venn diagram union.
Examples:
Suppose you have two Tables, with a single column each, and data as follows:
A B
- -
1 3
2 4
3 5
4 6
Note that (1,2) are unique to A, (3,4) are common, and (5,6) are unique to B.
Inner join:
An inner join using either of the equivalent queries gives the intersection of the two tables, i.e. the two rows they have in common.
select *
from a
INNER JOIN b on a.a = b.b;
select a.*,b.*
from a,b
where a.a = b.b;
a | b
--+--
3 | 3
4 | 4
Left outer join:
A left outer join will give all rows in A, plus any common rows in B.
select *
from a
LEFT OUTER JOIN b on a.a = b.b;
select a.*,b.*
from a,b
where a.a = b.b(+);
a | b
--+-----
1 | null
2 | null
3 | 3
4 | 4
Full outer join:
A full outer join will give you the union of A and B, i.e. All the rows in A and all the rows in B. If something in A doesn't have a corresponding datum in B, then the B portion is null, and vice versa.
select *
from a
FULL OUTER JOIN b on a.a = b.b;
a | b
-----+-----
1 | null
2 | null
3 | 3
4 | 4
null | 6
null | 5
select min(id) as id,address, retailer
from table1
group by address, retailer
order by id
The query you need is:
SELECT min(id), address, retailer
FROM table1 AS t1
group by address, retailer
order by address
Here's the source
Use This: It's working:
SELECT * FROM `sampletable` GROUP BY address, retailer
I'm doing 2 joins on the same table and I want the following results:
chnl_ptnr_key type1_ky type2_ky
------------- -------- --------
1 1 null
1 2 null
1 null 3
1 null 4
But instead I'm getting
chnl_ptnr_key type1_ky type2_ky
------------- -------- --------
1 1 3
1 2 3
1 2 3
1 2 4
My query is:
SELECT cp.chnl_ptnr_ky, cpmap1.ky as type1_ky, cpmap2.ky as type2_ky
FROM chnl_ptnr cp
LEFT OUTER JOIN chnl_ptnr_oos_map cpmap1 on (cp.chnl_ptnr_ky = cpmap1.chnl_ptnr_ky and cpmap1.typ = 'TYPE1')
LEFT OUTER JOIN chnl_ptnr_oos_map cpmap2 on (cp.chnl_ptnr_ky = cpmap2.chnl_ptnr_ky and cpmap2.typ = 'TYPE2')
WHERE cp.chnl_ptnr_ky = '1111'
Can someone help me to change this query so I get nulls in type1_ky and type2_ky where the row is being returned from the other join?
I need this format because I'm attempting to use it for an iBATIS map.
Many thanks
In your example, the results of the first LEFT JOIN are (1,1) and (1,2). As there are no (1,NULL) records, there will be no (1,NULL,?) records after the next LEFT JOIN.
You probably need a UNION in there somewhere...
SELECT cp.chnl_ptnr_ky, cpmap1.ky as type1_ky, NULL AS type2_ky
FROM chnl_ptnr cp
LEFT OUTER JOIN chnl_ptnr_oos_map cpmap1 on (cp.chnl_ptnr_ky = cpmap1.chnl_ptnr_ky and cpmap1.typ = 'TYPE1')
WHERE cp.chnl_ptnr_ky = '1111'
UNION ALL
SELECT cp.chnl_ptnr_ky, NULL, cpmap2.ky as type2_ky
FROM chnl_ptnr cp
LEFT OUTER JOIN chnl_ptnr_oos_map cpmap2 on (cp.chnl_ptnr_ky = cpmap2.chnl_ptnr_ky and cpmap2.typ = 'TYPE2')
WHERE cp.chnl_ptnr_ky = '1111'