In my database I have these two tables:
Person
+----+---------+---------+
| pk | name | sirname |
+----+---------+---------+
| 1 | john | leno |
| 2 | william | wallice |
| 3 | eva | apple |
| 4 | walter | white |
+----+---------+---------+
Request
+----+-------------+----------+---------------+---------+---------+
| pk | requestdate | accepted | requestperson | parent1 | parent2 |
+----+-------------+----------+---------------+---------+---------+
| 1 | 1/1/2014 | Y | 1 | 2 | 3 |
| 2 | 1/2/2014 | N | 4 | NULL | NULL |
+----+-------------+----------+---------------+---------+---------+
To get the requests I do:
SELECT *
FROM request
LEFT JOIN person p_subject ON requestperson = p_subject.pk
LEFT JOIN person p_parent1 ON parent1 = p_parent1.pk
LEFT JOIN person p_parent2 ON parent2 = p_parent2.pk
This works perfect but when I want to create a VIEW:
CREATE VIEW v_request AS
SELECT *
FROM request
LEFT JOIN person p_subject ON requestperson = p_subject.pk
LEFT JOIN person p_parent1 ON parent1 = p_parent1.pk
LEFT JOIN person p_parent2 ON parent2 = p_parent2.pk
I get this error: ORA-00957: duplicate column name
I do not want to rename all columns manually. How can I fix this?
Your view would consist of:
three columns with the columnname pk
three columns with the columnname name (which is not a good columnname)
three columns with the columnname sirname
because the tablealiases will not be prepended automatically (which the error ORA-00957: duplicate column name states exactly)
I am quite sure you will have to rename them manually to subject_pk, subject_name, subject_sirname and so on.
Related
We have various tables pertaining to different entities where we would like to globalize the stored values. We do not know how to proceed technically anymore and are open to any form of help, hints or tips.
Language
ID | Culture | Description |
---+---------+-------------+
1 | EN | English |
2 | FR | French |
3 | ES | Spanish |
Job
ID | Description |
---+-------------+
1 | Doctor |
2 | Firefighter |
JobGlobalization
ID | JobID | Description | Culture |
---+-------+-------------+---------+
1 | 1 | Docteur | FR |
2 | 1 | Doctora | ES |
We attempted to use CROSS JOIN to obtain something of the following:
ID | Description | Culture |
---+-------------+---------+
1 | Doctor | EN |
1 | Doctor | FR |
1 | Doctor | ES |
2 | Firefighter | ES |
2 | Firefighter | ES |
2 | Firefighter | ES |
Query used:
SELECT Job.ID, Job.Description, Language.Culture
CROSS JOIN Language
ORDER BY Job.ID
We experienced with different joins on the child globalization table in order to correlate the entities together, however the results set kept multiplying itself in the wrong way.
We would like that for every parent entity, whether it has any related child entities, a row is selected for every culture in the Language table. The description column will default to the parent entity in the case where there are no associated records in the child table.
The resulting table should be as follows:
ID | Description | Culture |
---+-------------+---------+
1 | Doctor | EN |
1 | Docteur | FR |
1 | Doctora | ES |
2 | Firefighter | EN |
2 | Firefighter | FR |
2 | Firefighter | ES |
We had in mind a condition that would select the 'Description' column from the parent table 'Job' if there were no corresponding record for it in the child table.
e.g.
IIF(JobGlobalization.Description IS NOT NULL, JobGlobalization.Description, Job.Description)
We attempted to use CROSS JOIN to obtain something of the following:
This should produce the result set you describe:
SELECT j.ID, j.Description, l.Culture
FROM Job j CROSS JOIN
Language l
ORDER BY j.ID, l.Culture;
You can insert this into JobGlobalization (although you might want to truncate it first). Or you can use CREATE TABLE AS (or the equivalent for your database) to create JobGlobalization from scratch.
You would then need to update this table with the appropriate values for the culture.
I have the following data:
select * from art_skills_table;
+----+------+---------------------------+
| ID | Name | skills |
+----+------+---------------------------|
| 1 | Anna | ["painting","photography"]|
| 2 | Bob | ["drawing","sculpting"] |
| 3 | Cat | ["pastel"] |
+----+------+---------------------------+
select * from computer_table;
+------+------+-------------------------+
| ID | Name | skills |
+------+------+-------------------------+
| 1 | Anna | ["word","typing"] |
| 2 | Cat | ["code","editing"] |
| 3 | Bob | ["excel","code"] |
+------+------+-------------------------+
I would like to write an SQL statement which results in the following table.
+------+------+-----------------------------------------------+
| ID | Name | skills |
+------+------+-----------------------------------------------+
| 1 | Anna | ["painting","photography","word","typing"] |
| 2 | Bob | ["drawing","sculpting","excel","code"] |
| 3 | Cat | ["pastel","code","editing"] |
+------+------+-----------------------------------------------+
I've tried something like SELECT * from art_skills_table LEFT JOIN computer_table ON name. However it doesn't give what I need. I've read about array_cat but I'm having a bit of trouble implementing it.
if the skills column from both tables are arrays, then you should be able to get away with this:
SELECT a.ID, a.name, array_cat(a.skills, c.skills)
FROM art_skills_table a LEFT JOIN computer_table c
ON c.id = a.id
That said, While you used LEFT join in your sample, I think either an INNER or FULL (OUTER) join might serve you better.
First, i wondered why the data are stored in such a model.
Was of the opinion that NoSQL databases lack ability for joins and ...
... a semantic triple would be in the form of subject–predicate–object.
... a Key-value (KV) stores use associative arrays.
... a relational database would be normalized.
A few information about the use case would have helped.
Nevertheless, you can select the data with CONCAT and REPLACE for the desired form.
SELECT art_skills_table.ID, computer_table.name,
CONCAT(
REPLACE(art_skills_table.skills, '}',','),
REPLACE(computer_table.skills, '{','')
)
FROM art_skills_table JOIN computer_table ON art_skills_table.ID = computer_table.ID
The query returns the following result:
+----+------+--------------------------------------------+
| ID | Name | Skills |
+----+------+--------------------------------------------+
| 1 | Anna | {"painting","photography","word","typing"} |
| 2 | Cat | {"drawing","sculpting","code","editing"} |
| 3 | Bob | {"pastel","excel","code"} |
+----+------+--------------------------------------------+
I've used the ID for the JOIN, even though Bob has different values.
The JOIN should probably be done over the name.
JOIN computer_table ON art_skills_table.Name = computer_table.Name
BTW, you need to tell us what SQL engine you're running on.
I am trying to figure out the best way to use a JOIN in MSSQL in order to do the following:
I have two tables. One table contains technician IDs and an example of one data set would be as follows:
+--------+---------+---------+---------+---------+
| tagid | techBid | techPid | techFid | techMid |
+--------+---------+---------+---------+---------+
| 1-1001 | 12 | 0 | 11 | 6 |
+--------+---------+---------+---------+---------+
I have another table that stores the names of these technicians:
+------+-----------+
| TTID | SHORTNAME |
+------+-----------+
| 11 | Steven |
| 12 | Mark |
| 6 | Pierce |
+------+-----------+
If the ID of a technician in the first table is 0, there is no technician of that type for that row (types are either B, P, F, or M).
I am trying to come up with a query that will give me a result that contains all of the data from table 1 along with the shortnames from table 2 IF there is a matching ID, so the result would look something like the following:
+--------+---------+---------+---------+---------+----------------+----------------+----------------+----------------+
| tagid | techBid | techPid | techFid | techMid | techBShortName | techPShortName | techFShortName | techMShortName |
+--------+---------+---------+---------+---------+----------------+----------------+----------------+----------------+
| 1-1001 | 12 | 0 | 11 | 6 | Mark | NULL | Steven | Pierce |
+--------+---------+---------+---------+---------+----------------+----------------+----------------+----------------+
I am trying to use a JOIN to do this, but I cannot figure out how to join on multiple columns multiple times to where it would look something like
Select table1.tagid, table1.techBid, table1.techPid, table1.techFid, table1.techMid, table2.shortname
FROM table1
INNER JOIN table2 on //Dont know what to put here
You need to use left joins like this:
Select table1.tagid, table1.techBid, table1.techPid, table1.techFid, table1.techMid,
t2b.shortname, t2p.shortname, t2f.shortname, t2m.shortname,
FROM table1
LEFT JOIN table2 t2b on table1.techBid = t2b.ttid
LEFT JOIN table2 t2p on table1.techPid = t2p.ttid
LEFT JOIN table2 t2f on table1.techFid = t2f.ttid
LEFT JOIN table2 t2m on table1.techMid = t2m.ttid
you just do mutiple left join
select tech.techPid, techPname.SHORTNAME
, tech.techFid, techFname.SHORTNAME
from tech
left join techName as techPname
on tech.techPid = techPname.TTID
left join techName as techFname
on tech.techFid = techFname.TTID
I'm trying to make a query that pair a worker that work on the same place. The relational model I'm asking looks like this:
Employee(EmNum, name)
Work(FiNum*, EmNum*)
Field(FiNum, Title)
(bold indicates primary key)
right now my code looks like
SELECT work.finum, e1.name,e1.emnum,e2.name,e2.emnum
FROM employee e1
INNER JOIN employee e2
on e1.EmNum = e2.EmNum
INNER JOIN work
on e1.emnum = work.emnum
This gives me result like
| finum | name | emnum | name_1 | emnum_1 |
| 1 | a | 1 | a | 1 |
| 1 | b | 2 | b | 2 |
| 2 | c | 3 | c | 3 |
| 3 | d | 4 | d | 4 |
| 3 | e | 5 | e | 5 |
while I want the result to be like
| finum | name | emnum | name_1 | emnum_1 |
| 1 | a | 1 | b | 2 |
| 1 | b | 2 | a | 1 |
| 3 | d | 4 | e | 4 |
| 3 | e | 5 | d | 5 |
I'm quite new at sql so I can't really think of a way to do this. Any help or input would be helpful.
Thanks
Your question is slightly unclear, but my guess is that you're trying to find employees that worked on the same place = same finum in work, but different row. That you can do this way:
SELECT w1.finum, e1.name,e1.emnum, e2.name,e2.emnum
from work w1
join work w2 on w1.finum = w2.finum and w1.emnum != w2.emnum
join employee e1 on e1.emnum = w1.emnum
join employee e2 on e2.emnum = w2.emnum
If you don't want to repeat the records (1 <-> 2 + 2 <-> 1 change the != in the join to > or <)
I'm trying to make a query that pair a worker that work on the same place.
Presumably the "places" are represented by the Field table. If you want to pair up employees on that basis then you should be performing a join conditioned on field numbers being the same, as opposed to one conditioned on employee numbers being the same.
It looks like your main join wants to be a self-join of Work to Work of records with matching FiNum. To get the employee names in the result then you will need also to join Employee twice. To avoid employees being paired with themselves, you will want to filter those cases out via a WHERE clause.
If this is a stupid question, forgive me, I'm not very familiar with PostgreSQL.
I've collected inventory data from used car dealerships in my area and stored it in a postgreSQL table. I've got a second table with particular details regarding certain makes and models. For example:
The dealership table is structured like so:
-----------------------------------------
| Dealership | Make | Model | Year | ID |
----------------------------------------|
| A | Ford | F250 | 2003 | 1 |
| A | Chevy| Cobalt| 2005 | 2 |
| B | Ford | F250 | 2003 | 1 |
| B | Dodge| Chrgr | 2012 | 3 |
-----------------------------------------
The details table is structured like so:
-----------------------------------------
| ID | DetailA| DetailB| DetailC|
-----------------------------------------
| 1 | data | data | data |
| 2 | data | data | data |
| 3 | data | data | data |
| 4 | data | data | data |
-----------------------------------------
My goal is to retrieve vehicle matches from multiple dealerships and display the appropriate details. In the above example, I would like to see:
-----------------------------------------------------
| Make | Model | Year | DetailA | DetailB | DetailC |
-----------------------------------------------------
| Ford | F250 | 2003 | data | data | data |
-----------------------------------------------------
With this result, I will know that both A and B havea 2003 Ford F250 for sale, and can view the related details of the vehicle.
I've tried many different queries, but most are variations on something like this:
SELECT DISTINCT
dealership_table.make,
dealership_table.model,
dealership_table.year
details_table.detaila,
details_table.detailb,
details_table.detailc
FROM
dealership_table
INNER JOIN
details_table
ON
dealership_table.id = details_table.id
WHERE
dealership_table.dealership = 'A'
OR
dealership_table.dealership = 'B'
However this returns all of the distinct matches from the table where dealership is either A or B. I've tried multiple inner-joins, but I an error complaining details_table is specified multiple times.
If I'm doing something really silly, I apologize. Like I said before, I'm pretty much an SQL noob.
What am I doing wrong? How should I go about retrieving the desired results? Any suggestions, solutions, or advice is greatly appreciated!
You can write:
SELECT dealership_table1.make,
dealership_table1.model,
dealership_table1.year,
details_table.detaila,
details_table.detailb,
details_table.detailc
FROM dealership_table dealership_table1
JOIN dealership_table dealership_table2
ON dealership_table1.make = dealership_table2.make
AND dealership_table1.model = dealership_table2.model
AND dealership_table1.year = dealership_table2.year
JOIN details_table
ON dealership_table.id = details_table.id
WHERE dealership_table1.dealership = 'A'
AND dealership_table1.dealership = 'B'
;
(Note that the FROM dealership_table dealership_table1 and JOIN dealership_table dealership_table2 set up distinct "aliases", so you can use the same table multiple different times in the same query without getting name-conflicts.)
I may be misunderstanding your table layout, but I think you should consider changing to a different structure. Here's what I would propose:
Vehicle:
----------------------------
| ID | Make | Model | Year |
----------------------------
| 1 | Ford | F250 | 2003 |
| 2 | Chevy| Cobalt| 2005 |
| 3 | Dodge| Chrgr | 2012 |
----------------------------
Dealership:
----------------------------
| Dealership | ID | Detail |
----------------------------
| A | 1 | data |
| A | 2 | data |
| B | 1 | data |
| B | 3 | data |
----------------------------
This way you're not storing vehicle information (make/model/year) in more than one place.
Here's how you would write your desired query given the above schema:
SELECT Make, Model, Year, A.Detail, B.Detail, C.Detail
FROM Vehicle V
LEFT OUTER JOIN Dealership A on A.Dealership = 'A' and A.id = V.id
LEFT OUTER JOIN Dealership B on B.Dealership = 'B' and B.id = V.id
LEFT OUTER JOIN Dealership C on C.Dealership = 'C' and C.id = V.id