Say I have 2 distinct tables in SSIS from 2 different servers.
Table 1 Table 2
Animal Age Owner Location
Dog 10 Bill IL
Dog 7 Kelly CA
Cat 4 Tom TX
I want to have one single result table that is
Result Table
Animal Age Owner Location
Dog 10 NULL NULL
Dog 7 NULL NULL
Cat 4 NULL NULL
NULL NULL Bill IL
NULL NULL Kelly CA
NULL NULL Tom TX
a UNION should fit:
select animal, age, null as owner, null as location from animal
union
select null as animal, null as age, owner, location from owner
If you want to join two datasets without any join logic (No key in common) you need to:
Create a fake key column in each dataset (With derived column for exemple, value of the fake column should be different in each dataset)
Sort these fake key columns
Use a full outer join merge based on these fake relations
You make think it's a weird way to do, that is because it's a weird result you are trying to obtain, maybe could you explain your initial need ?
You should use merge component from SSIS tools. If you want FULL OUTER JOIN you will choose that in the editor of component.
But first of all you need to go to the Input and Output Properties tab and in the OLE DB Source Output set the IsSorted property value to True.(You need to make sure that the input data is truly sorted though.)
Related
Am Having the Tables in SQL server as Super and Sub types like below. Now if i have to get list of Furnitures then how can i get the list?
Furniture table:
Id FurnituretypeId NoofLegs
-------------------------------
1 1 4
2 2 4
FurnitureType table:
Id Name
-----------------
1 chair
2 cot
3 table
Chair Table:
Id Name CansSwing CanDetachable FurnitureId
------------------------------------------------------------
1 Chair1 Y Y 1
Cot Table:
Id Name CotType Storage StorageType FurnitureId
-------------------------------------------------------------------
1 Cot1 Auto Y Drawer 2
How can i get the entire furniture list as some of them are chair and some of them are cot. How can i join the these tables with furniture table and get the list?
Hmmm . . . union all and join?
select cc.*, f.*
from ((select Id, Name, CansSwing, CanDetachable,
NULL as CotType, NULL as Storage, NULL as StorageType, FurnitureId
from chairs
) union all
(select Id, Name, NULL as CansSwing, NULL as CanDetachable,
CotType, Storage, StorageType, FurnitureId
from cots
)
) cc join
furniture f
on cc.furnitureid = f.id;
This is a classical learning problem, that's why I'm not giving you the code to solve this but all the insights you need to do so.
You have multiple approaches possible, but I'm describing two simple ones:
1) Use the UNION statement to join two separate queries one for Chair and the other for Cot, bare in mind that both SELECT have to return the same structure.
SELECT
a1,
a2,
etc..
FROM table1 a1
JOIN table2 a2 ON a1.some = a2.some
UNION
SELECT
a1,
a3,
etc..
FROM table1 a1
JOIN table3 a3 ON a1.some = a3.some
2) You can do it all in one SELECT statement using a LEFT JOIN to both tables and and in the select using COALESCE or ISNULL to get the values for one table or the other. In the WHERE condition you have to force one or the other join to be not null.
SELECT
a1,
COALESCE(a2,a3) as col2
FROM table1
LEFT JOIN table2 a2 ON a1.some = a2.some
LEFT JOIN table3 a3 ON a1.some = a3.some
WHERE
a2.some IS NOT NULL
OR a3.some IS NOT NULL
Mapping objects into relational models takes a degree of understanding of what is possible vs. what is wise in an RDBMS. Object oriented database systems tried to go after problems like this (generally without much success) precisely because the problem statement is arguably not the right one.
Please consider just putting all of these in one table. Then use null for the fields that don't really matter for each sub-type. You will likely end up being a lot happier in the end since you can spend less time at runtime doing joins and instead just query the information you need and use indexing on the same table to find the fasted path for each query you want to run.
SELECT * FROM CombinedTable;
Consider i have 2 queries with the below result set...First result set is for students, so all the columns pertaining to instructors are null.. The second result set is pertaining to instructors and column related to students are null and both of them share few common columns..
Student:
uid f_name m_name l_name class school Section Dept. Branch Title
1 abc c dey 2 NYU 1 null null null
2 cde d rey 3 CU 2 null null null
3 xyz r mey 4 LSU 3 null null null
Teacher:
uid f_name m_name l_name class school Section Dept. Branch Title
4 wss c tey null null null Science Biology Asso.Prof
2 cde d rey null null null Arts Music Asso.Prof
5 rrr r jey null null null Science Chemistry Prof
If you look in the above result set, UID 2 is common in both the result set, that basically means a professor can also be a student at the same time... Now i want to join/merge these two queries into a common resultset say 'Users' who are basically the teachers and students.
The result set of 'Users' should be unique with respect to UID. If i use union all, there will be duplicates on UID 2. I need a query which can merge the columns for a single row... The result set should be:
1 abc c dey 2 NYU 1 null null null
2 cde d rey 3 CU 2 Arts Music Asso.Prof
3 xyz r mey 4 LSU 3 null null null
4 wss c tey null null null Science Biology Asso.Prof
5 rrr r jey null null null Science Chemistry Prof
Note 2 above, it has both student and professor details in one row...
How can i achieve this in Oracle ? Appreciate your help.
As has been mentioned in Comments, this is a poor design (or perhaps a poor solution using a good design). If the base tables are "person" (containing only information that is of the same kind for students and instructors, such as UID, name, date of birth, email etc.), "student" (with UID as foreign key, and showing only characteristics specific to students) and "teacher" (same for teachers or instructors), then the design is fine, and your desired final output can be obtained directly from these base tables, not from the results of other queries you have written. jva shows something along these lines in his/her answer.
If you really have to put up with it, the way to use your existing queries is to use union all - but then you must group by uid, and for each column you must select max(...) - for example max(f_name) and max(school). Use column aliases in the SELECT clause, for example select .... , max(school) as school, ...
Or, slightly more efficiently (but with some risks), group by id, f_name, m_name, l_name and select max(...) only for the remaining columns. The risk is that in one place the m_name is N and in the other it is null; that is, your data is internally inconsistent. (If it all comes from one base table, "person", then this risk shouldn't exist.)
This would be the general approach:
SELECT persons.id
,nvl(<some_student_field>, <same_teacher_field) as some_common_field
,...
FROM persons
LEFT OUTER JOIN students on (person.id = students.person_id)
LEFT OUTER JOIN teachers on (person.id = teachers.person_id)
WHERE <mandatory_field_for_students> IS NOT NULL
OR <mandatory_field_for_teachers> IS NOT NULL
I have two tables, specifically, they contain standard and specific parameters respectively.
Table1:
PKParameter Name Unit
1 Temperature K
2 Length mm
3 Pressure bar
Table2:
PKSpecParam Name Unit
1 Weight kg
2 Area m2
PKParameter ans PKSpecParameter are primary keys
I would like to combine these two tables into a third table which will keep track of the primary keys so I can reference any of the parameters, regardless of the table they are from.
For example:
PKCombined PKParameter PKSpecParameter
1 1 NULL
2 2 NULL
3 3 NULL
4 NULL 1
5 NULL 2
Now I would like to use PKCombined primary key to reference parameter
Maybe there is a better way to do this, but I've just started meddling with databases.
Select a.PKParameter , a.name,a.unit,b.PKSpecParam , b.name,b.unit
from table1 a outer join table2 b on a.pkparameter=b.pkspecparam
However, this will give out null values if number of entries in pkparameter and pkspecparam dont match
I have a database on access and I want to add a value to a column at the end of each row based on which hospital they are in. This is a separate value. For example - the hospital called "St. James Hospital" has the id of "3" in a separate field. How do I do this using a query rather than manually going through a whole database?
example here
Not the best solution, but you can do something like this:
create table new_table as
select id, case when hospital="St. James Hospital" then 3 else null
from old_table
Or, the better option would be to create a table with the columns hospital_name and hospital_id. You can then create a foreign key relationship that will create the mapping for you, and enforce data integrity. A join across the two tables will produce what you want.
Read about this here:
http://net.tutsplus.com/tutorials/databases/sql-for-beginners-part-3-database-relationships/
The answer to your question is a JOIN+UPDATE. I am fairly sure if you looked up you would find the below link.
Access DB update one table with value from another
You could do this:
update yourTable
set yourFinalColumnWhateverItsNameIs = {your desired value}
where someColumn = 3
Every row in the table that has a 3 in the someColumn column will then have that final column set to your desired value.
If this isn't what you want, please make your question clearer. Are you trying to put the name of the hospital into this table? If so, that is not a good idea and there are better ways to accomplish that.
Furthermore, if every row with a certain value (3) gets this value, you could simply add it to the other (i.e. Hospitals) table. No need to repeat it everywhere in the table that points back to the Hospitals table.
P.S. Here's an example of what I meant:
Let's say you have two tables
HOSPITALS
id
name
city
state
BIRTHS
id
hospitalid
babysname
gender
mothersname
fathername
You could get a baby's city of birth without having to include the City column in the Births table, simply by joining the tables on hospitals.id = births.hospitalid.
After examining your ACCDB file, I suggest you consider setting up the tables differently.
Table Health_Professionals:
ID First Name Second Name Position hospital_id
1 John Doe PI 2
2 Joe Smith Co-PI 1
3 Sarah Johnson Nurse 3
Table Hospitals:
hospital_id Hospital
1 Beaumont
2 St James
3 Letterkenny Hosptial
A key point is to avoid storing both the hospital ID and name in the Health_Professionals table. Store only the ID. When you need to see the name, use the hospital ID to join with the Hospitals table and get the name from there.
A useful side effect of this design is that if anyone ever misspells a hospital name, eg "Hosptial", you need correct that error in only one place. Same holds true whenever a hospital is intentionally renamed.
Based on those tables, the query below returns this result set.
ID Second Name First Name Position hospital_id Hospital
1 Doe John PI 2 St James
3 Johnson Sarah Nurse 3 Letterkenny Hosptial
2 Smith Joe Co-PI 1 Beaumont
SELECT
hp.ID,
hp.[Second Name],
hp.[First Name],
hp.Position,
hp.hospital_id,
h.Hospital
FROM
Health_Professionals AS hp
INNER JOIN Hospitals AS h
ON hp.hospital_id = h.hospital_id
ORDER BY
hp.[Second Name],
hp.[First Name];
Goal is to replace a integer value that is returned in a SQL query with the char value that the number represents. For example:
A table attribute labeled ‘Sport’ is defined as a integer value between 1-4. 1 = Basketball, 2 = Hockey, etc. Below is the database table and then the desired output.
Database Table:
Player Team Sport
--------------------------
Bob Blue 1
Roy Red 3
Sarah Pink 4
Desired Outputs:
Player Team Sport
------------------------------
Bob Blue Basketball
Roy Red Soccer
Sarah Pink Kickball
What is best practice to translate these integer values for String values? Use SQL to translate the values prior to passing to program? Use scripting language to change the value within the program? Change database design?
The database should hold the values and you should perform a join to another table which has that data in it.
So you should have a table which has say a list of people
ID Name FavSport
1 Alex 4
2 Gnats 2
And then another table which has a list of the sports
ID Sport
1 Basketball
2 Football
3 Soccer
4 Kickball
Then you would do a join between these tables
select people.name, sports.sport
from people, sports
where people.favsport = sports.ID
which would give you back
Name Sport
Alex Kickball
Gnat Football
You could also use a case statement eg. just using the people table from above you could write something like
select name,
case
when favsport = 1 then 'Basketball'
when favsport = 2 then 'Football'
when favsport = 3 then 'Soccer'
else 'Kickball'
end as "Sport"
from people
But that is certainly not best practice.
MySQL has a CASE statement. The following works in SQL Server:
SELECT
CASE MyColumnName
WHEN 1 THEN 'First'
WHEN 2 THEN 'Second'
WHEN 3 THEN 'Third'
ELSE 'Other'
END
In oracle you can use the DECODE function which would provide a solution where the design of the database is beyond your control.
Directly from the oracle documentation:
Example: This example decodes the value warehouse_id. If warehouse_id is 1, then the function returns 'Southlake'; if warehouse_id is 2, then it returns 'San Francisco'; and so forth. If warehouse_id is not 1, 2, 3, or 4, then the function returns 'Non domestic'.
SELECT product_id,
DECODE (warehouse_id, 1, 'Southlake',
2, 'San Francisco',
3, 'New Jersey',
4, 'Seattle',
'Non domestic') "Location"
FROM inventories
WHERE product_id < 1775
ORDER BY product_id, "Location";
The CASE expression could help. However, it may be even faster to have a small table with an int primary key and a name string such as
1 baseball
2 football
etc, and JOIN it appropriately in the query.
Do you think it would be helpful to store these relationships between integers and strings in the database itself? As long as you have to store these relationships, it makes sense to store it close to your data (in the database) instead of in your code where it can get lost. If you use this solution, this would make the integer a foreign key to values in another table. You store integers in another table, say sports, with sport_id and sport, and join them as part of your query.
Instead of SELECT * FROM my_table you would SELECT * from my_table and use the appropriate join. If not every row in your main column has a corresponding sport, you could use a left join, otherwise selecting from both tables and using = in the where clause is probably sufficient.
definitely have the DB hold the string values. I am not a DB expert by any means, but I would recommend that you create a table that holds the strings and their corresponding integer values. From there, you can define a relationship between the two tables and then do a JOIN in the select to pull the string version of the integer.
tblSport Columns
------------
SportID int (PK, eg. 12)
SportName varchar (eg. "Tennis")
tblFriend Columns
------------
FriendID int (PK)
FriendName (eg. "Joe")
LikesSportID (eg. 12)
In this example, you can get the following result from the query below:
SELECT FriendName, SportName
FROM tblFriend
INNER JOIN tblSport
ON tblFriend.LikesSportID = tblSport.SportID
Man, it's late - I hope I got that right. by the way, you should read up on the different types of Joins - this is the simplest example of one.