I got a problems in combining tables
I have 2 table:
t1:
id | name
----- ---------
1 | 'foo'
2 | 'bar'
t2:
id | type
------ ---------
1 | 'type1'
3 | 'type2'
I want to combine those tables into 1 result set and make all attributes of same primary key in 1 row. And with single SQL statement in Oracle. The primary key column with the same name (id in the sample) can't appear twice
The result should be:
id | name | type
----- --------- ---------
1 | 'foo' | 'type1'
2 | 'bar' | null
3 | null | 'type2'
Thanks in advance for any ideas and responses.
Update:
I tried Ani Menon's out join statement, but not 100% the expected result. The outer join gives null value if id exists in t1 but not in t2.
SELECT t1.id,t1.name,t2.type
FROM t1
FULL OUTER JOIN t2 ON t1.id=t2.id;
Returns
id | name | type
----- --------- ---------
1 | 'foo' | 'type1'
2 | 'bar' | null
null | null | 'type2'
Do a full outer join:
SELECT table1.id,table1.name,table2.type
FROM table1
FULL OUTER JOIN table2 ON table1.id=table2.id;
Edit:
Use coalesce(table1.id,table2.id) in place of table1.id in the query.
Similar to Ani's answer, but won't give you the null id:
select coalesce(table1.id, table2.id) as id, table1.name, table2.type
from table1 full outer join table2 on table1.id = table2.id;
might now be the optimal solution but this will work.
select allIDs.id, t1.name, t2.type
(select id from t1
union
select id from t2) allIDs left outer join t1 on allIDs.id = t1.id left outer join t2 on allIDs.id = t2.id
tested in sql server worked.
create table t1 (
id int,
name varchar(25)
)
create table t2
(
id int,
type varchar(25)
)
insert into t1
values(1, 'fool'),
(2,'bar')
insert into t2
values(1,'type1'),
(3,'type2')
select id, MAX(name) name, MAX(type) type from(
select id, name, null type from t1
union all
select id, null name, type from t2) combine group by id
SELECT t1.id,t1.name,t2.type
FROM t1
LEFT OUTER JOIN t2 ON t1.id=t2.id
union
select t2.id, t1.name, t2.type
from t2
left outer join t1 on t2.id = t1.id
Related
I'm trying to find a simple solution for my SQL Server problem.
I have two tables look like this:
table1
--id
-- data
table2
--id
--table1_id
--value
I have some records like this:
Table1
+-----------------------+
| id | data |
+-----------------------+
| 1 | ? |
+-----------------------+
| 2 | ? |
+-----------------------+
Table2
+-----------------------+
|id | table1_id | value |
+-----------------------+
| 1 | 1 | 'a' |
+-----------------------+
| 2 | 1 | 'b' |
+-----------------------+
| 3 | 2 | 'a' |
+-----------------------+
Now I want to get table1 with all it's additional values where the relation to table2 has 'a' AND 'b' as values.
So I would get the id 1 of table1.
Currently I have an query like this:
SELECT t1.[id], t1.[data]
FROM [table1] t1,
(SELECT [id]
FROM [table1] t1
JOIN [table2] t2 ON t1.[id] = t2.[table1_id] AND t2.[Value] IN('a', 'b')
GROUP BY t1[id]
HAVING COUNT(t2.[Value]) = 2) x
WHERE t1.id = x.id
Has anyone an idea on how to achieve my goal in a simpler way?
One way uses exists:
select t1.*
from table1 t1
where exists (select 1
from table2 t2
where t2.table1_id = t1.id and t2.value = 'a'
) and
exists (select 1
from table2 t2
where t2.table1_id = t1.id and t2.value = 'b'
);
This can take advantage of an index on table2(table1_id, value).
You could also write:
select t1.*
from table1 t1
where (select count(distinct t2.value)
from table2 t2
where t2.table1_id = t1.id and t2.value in ('a', 'b')
) = 2 ;
This would probably also have very good performance with the index, if table2 doesn't have duplicates.
SELECT T1.[id], T1.[data]
FROM table1 AS T1
JOIN table2 AS T2
ON T1.[id]=T2.[table1_id]
JOIN table2 AS T3
ON T1.[id]=T3.[table1_id]
WHERE
T2.[Value] ='a'
AND T3.[Value] = 'b'
As Gordon Linoff suggested, exists clause usage works as well and could be performance efficient depending on the data you are playing with.
you have to do several steps to solve the problem:
established which records are related to table 1 and table 2 and which of these are of value (A or B) and eliminate the repeated ones with the group by(InfoRelationate )
validate that only those related to a and b were allowed by means of a count in the table above (ValidateAYB)
see what data meets the condition of table1 and table 2 and joined table 1
this query meets the conditions
with InfoRelationate as
(
select Table2.table1_id,value
from Table2 inner join
Table1 on Table2.table1_id=Table1.id and Table2.value IN('a', 'b')
group by Table2.table1_id,value
),
ValidateAYB as
(
select InfoRelationate.table1_id
from InfoRelationate
group by InfoRelationate.table1_id
having count (1)=2
)
select InfoRelationate.table1_id,InfoRelationate.value
from InfoRelationate
inner join ValidateAYB on InfoRelationate.table1_id=ValidateAYB.table1_id
union all
select id,data
from Table1
Example code
------------------
| **table 1** |
------------------
| 1 | 400 |
| 2 | 220 |
| 3 | 123 |
------------------
| **table 2** |
------------------
| 1 | 100 |
formula : table1 - table2 where table1.id=table2.id
------------------
| **Result** |
------------------
| 1 | 300 |
| 2 | 220 |
| 3 | 123 |
You want an outer join to get all rows from table_1 and the matching ones from table2
select t1.id, t1.val - coalesce(t2.val, 0) as result
from table_1 t1
left join table_2 t2 on t1.id = t2.id;
The coalesce(t2.val, 0) is necessary because the outer join will return null for those rows where no id exists in table_2 but t1.val - null would yield null
select t1.id,
nvl2(t2.val,t1.val-t2.val,t1.val) val
from t1,t2
where t1.id=t2.id(+)
order by t1.id;
Try this
select t1.col1, t1.col2-t2.col1 as balance from
table1 t1 left join table2 t2 on t1.col1=t2.col1
I don't the syntax in Oracle sql, but I can give the solution in mysql.
Consider the table with 2 columns:
id , value
SELECT table1.id, table1.value - table2.value
FROM table1, table2
WHERE table1.id=table2.id
OR
SELECT table1.id, table1.value
FROM table1, table2
WHERE NOT (table1.id =table2.id)
In some cases using scalar subquery caching could give better performance. It is on developer to compare execution plans and decide which query is the most appropriate.
with t1 (id, num) as
(
select 1, 400 from dual union all
select 2, 220 from dual union all
select 3, 123 from dual
),
t2(id, num) as
(
select 1, 100 from dual
)
select id,
num - nvl((select num from t2 where t2.id = t1.id), 0) result
from t1;
This is just to show you a different technique for solving problems in which you try to get data from several tables, but some may not have matching rows.
Using outer join in this case is in my opinion more logical.
I have a table with this structure:
Table 1: ID(PK) | <other columns>
1 | otherdata
2 | otherdata
the other table, It´s a list of documents (PDF,DOC,etc) with a URL to download. these documents is stored in my network.
Table 2: ID | IDDOC | LINKDOC | INFO
1 | 1 | 'http://URL1' | 'Info1'
1 | 2 | 'http://URL2' | 'Info2'
2 | 1 | 'http://URL3' | 'Info3'
ID is the foreign key for Table 1,IDDOC is a foreign key to a 3rd table (below) that describe the document type:
Table 3: IDDOC | Name
1 | 'Contract'
2 | 'Notification'
I need to generate a query to join these tables and get a similar structure
ID | <SomeCollumsTable1> | NameDesc1 | NameURL1 | ... | NameDesc2 | NameURL2
Example output:
ID | <SomeCollumsTable1> | ContractDesc | ContractURL | NotificationDesc | NotificationURL
1 | otherdata | 'Info1' | 'http://URL1' | 'Info2' | 'http://URL2'
2 | otherdata | 'Info3' | 'http://URL3' | '' | ''
I.E. Generate many pairs Desc/URL as many records exits in "Table3". the sample data have 2 documents types and generate 4 columns.
Currently i have subquerys to each desired document, but sounds very inefficient for me, the query is big and new documents i add in "Table3" need change in the whole query and need to just adjust the Where clause to indicate why IDDOC´s need. (using a IN clause)
Or its better to manipulate this in my application (winforms/vb.net)?
The App generate a report in EXCEL format.
Please try the below query:
DECLARE #qu NVARCHAR(MAX), #pcol NVARCHAR(MAX)
SELECT #pcol= COALESCE(#pcol + ',','') + type FROM
(SELECT Name+N'URL' AS type FROM t3 UNION SELECT Name+N'Desc' AS type FROM t3 ) A
SET #qu=N'Select ID,b,c,'+ #pcol + N' FROM
(
SELECT t1.ID, t1.b,t1.c, t2.linkdoc as data,t3.Name +N''URL'' as Type FROM t1 LEFT JOIN t2 ON t1.ID=t2.ID
LEFT JOIN t3 ON t2.iddoc=t3.iddoc
UNION
SELECT t1.ID, t1.b, t1.c, t2.info as data, t3.Name +N''Desc'' as Type FROM t1 LEFT JOIN t2 ON t1.ID=t2.ID
LEFT JOIN t3 ON t2.iddoc=t3.iddoc
)S
PIVOT
(
MAX(data)
FOR Type IN ('+#pcol +N')) AS piv'
EXEC sp_executesql #qu
Here's a sql fiddle for you :
http://sqlfiddle.com/#!6/9fb46/1
EDIT:explanation added
So basically I am using PIVOT, except that PIVOT can be done on a
single column , in our case, either on URL or Desc columns. But we
need both these columns to be pivoted,so I used UNION to get both into
a single column data like below
SELECT t1.ID, t1.b,t1.c, t2.linkdoc as data,t3.Name +N'URL' as Type FROM t1 LEFT JOIN t2 ON t1.ID=t2.ID
LEFT JOIN t3 ON t2.iddoc=t3.iddoc
UNION
SELECT t1.ID, t1.b, t1.c, t2.info as data, t3.Name +N'Desc' as Type FROM t1 LEFT JOIN t2 ON t1.ID=t2.ID
LEFT JOIN t3 ON t2.iddoc=t3.iddoc
which I then used in PIVOT like this :
Select ID,b,c,[ContractURL],[ContractDesc],[NotificationURL],[NotificationDesc]
FROM
(
SELECT t1.ID, t1.b,t1.c, t2.linkdoc as data,t3.Name +N'URL' as Type FROM t1 LEFT JOIN t2 ON t1.ID=t2.ID
LEFT JOIN t3 ON t2.iddoc=t3.iddoc
UNION
SELECT t1.ID, t1.b, t1.c, t2.info as data, t3.Name +N'Desc' as Type FROM t1 LEFT JOIN t2 ON t1.ID=t2.ID
LEFT JOIN t3 ON t2.iddoc=t3.iddoc
)S
PIVOT
(
MAX(data)
FOR Type IN ([ContractURL],[ContractDesc],[NotificationURL],[NotificationDesc])
)piv
Now for making this dynamic I calculated all the unique columns from table t3 like
SELECT Name+N'URL' AS type FROM t3 UNION SELECT Name+N'Desc' AS type FROM t3
I am trying to join two tables one is a unique feature the seconds is readings taken on several dates that relate to the unique features. I want all of the records in the first table plus the most recent reading. I was able to get the results I was looking for before adding the shape field. By using the code
SELECT
Table1.Name, Table1.ID, Table1.Shape,
Max(Table2.DATE) as Date
FROM
Table1
LEFT OUTER JOIN
Table2 ON Table1.ID = table2.ID
GROUP BY
Table1.Name, Table1.ID, Table1.Shape
The shape field is a geometry type and I get the error
'The type "Geometry" is not comparable. It can not be use in the Group By Clause'
So I need to go about it a different way, but not sure how.
Below is a sample of the two tables and the desired results.
Table1
Name| ID |Shape
AA1 | 1 | X
BA2 | 2 | Y
CA1 | 3 | Z
CA2 | 4 | Q
Table2
ID | Date
1 | 5/27/2013
1 | 6/27/2014
2 | 5/27/2013
2 | 6/27/2014
3 | 5/27/2013
3 | 6/27/2014
My Desired Result is
Name| ID |Shape |Date
AA1 | 1 | X | 6/27/2014
BA2 | 2 | Y | 6/27/2014
CA1 | 3 | Z | 6/27/2014
CA2 | 4 | Q | Null
You can do the aggregation on Table2 in a CTE, finding the MAX(DATE) for each ID, and then join that result to Table1:
WITH AggregatedTable2(ID, MaxDate) AS
(
SELECT
ID, MAX(DATE)
FROM
Table2
GROUP BY
ID
)
SELECT
t1.ID, t1.Name, t1.Shape, t2.MaxDate
FROM
Table1 t1
LEFT JOIN
AggregatedTable2 t2 ON t1.ID = t2.ID
Try casting geometry as a varchar.
Select Table1.Name, Table1.ID, cast(Table1.Shape as varchar(1)) AS Shape, Max(Table2.DATE) as Date
FROM Table1 LEFT OUTER JOIN
Table2 ON Table1.ID = table2.ID
Group By Table1.Name, Table1.ID, cast(Table1.Shape as varchar(1))
Try this:
SELECT t1.Name
, t1.ID
, t1.Shape
, MAX(t2.Date) As Date
FROM Table1 AS t1
LEFT JOIN Table2 AS t2
ON t2.ID = t1.ID
GROUP
BY t1.Name
, t1.ID
, t1.Shape
I'm wondering if anybody can help me solve this question I got at a job interview. Let's say I have two tables like:
table1 table2
------------ -------------
id | name id | name
------------ -------------
1 | alpha 1 | alpha
3 | charlie 3 | charlie
4 | delta 5 | echo
8 | hotel 7 | golf
9 | india
The question was to write a SQL query that would return all the rows that are in either table1 or table2 but not both, i.e.:
result
------------
id | name
------------
4 | delta
5 | echo
7 | golf
8 | hotel
9 | india
I thought I could do something like a full outer join:
SELECT table1.*, table2.*
FROM table1 FULL OUTER JOIN table2
ON table1.id=table2.id
WHERE table1.id IS NULL or table2.id IS NULL
but that gives me a syntax error on SQL Fiddle (I don't think it supports the FULL OUTER JOIN syntax). Other than that, I can't even figure out a way to just concatenate the rows of the two tables, let alone filtering out rows that appear in both. Can somebody enlighten me and tell me how to do this? Thanks.
Well, you could use UNION instead of OUTER JOIN.
SELECT * FROM table1 t1
LEFT JOIN table2 t2 ON t1.id = t2.id
UNION
SELECT * FROM table1 t1
RIGHT JOIN table2 t2 ON t1.id = t2.id
Here's a little trick I know: not equals is the same as XOR, so you could have your WHERE clause something like this:
WHERE ( table1.id IS NULL ) != ( table2.id IS NULL )
select id,name--,COUNT(*)
from(
select id,name from table1
union all
select id,name from table2
) x
group by id,name
having COUNT(*)=1
I'm sure there are lots of solutions, but the first thing that comes to mind for me is to union all the two tables, then group by name, filter with a having clause on the count.
(
SELECT * FROM TABLE1
EXCEPT
SELECT * FROM TABLE2
)
UNION ALL
(
SELECT * FROM TABLE2
EXCEPT
SELECT * FROM TABLE1
)
This should work on most database servers
SELECT id, name
FROM table1
WHERE NOT EXISTS(SELECT NULL FROM table2 WHERE table1.id = table2.id AND table1.name = table2.name)
UNION ALL
SELECT id, name
FROM table2
WHERE NOT EXISTS(SELECT NULL FROM table1 WHERE table1.id = table2.id AND table1.name = table2.name)