Any ideas on how this should be done with T-SQL queries?
I have two tables, Table A contain records I want to return but filter through. Table B contains the list of filters and class categories. New records are added to Table A all the time. The goal is to dynamically categorized records in Table A based on the filters listed in Table B.
Example:
Table A
Name
------------
John Doe
Mary Lamb
Peter Pan
Tom Sawyer
Suzie Lamb
Nancy Lamb
Josh Reddin
Table B:
Filter | Category
----------------------
John%Doe% | Team 1
%Lamb% | Team 2
Tom% | Team 1
Desired output:
Name | Category
John Doe | Team 1
Tom Sawyer | Team 1
Mary Lamb | Team 2
Suzie Lamb | Team 2
Nancy Lamb | Team 2
Peter Pan |
Josh Reddin |
I thought about doing the following but not sure if that's the best solution:
SELECT Filter, category from TableB (Get list of filters)
Using SQL Loop through filters returned in (1.) and find matches in Table A using LIKE.
Example:
SELECT name, Category
FROM Table A, Table B
WHERE Table A.Name Like (CURRENT filter FROM B)
Insert/append record(s) returned in (2.) into TempTable
SELECT *
FROM TempTable (this returns Names and categories as shown in the desired output)
UNION
SELECT *
FROM Table A
RIGHT OUTER JOIN TempTable on NAME
WHERE Category in null
(This returns rows with no categories found...Peter Pan and Josh Reddin)
Any ideas?
How about performance?
Thanks.
You can use combination of like and left join
select a.Name,b.Category
from tableA a left join tableB b on a.name like b.Filter
Related
I have a database that stores customer information in 2 tables.
Table stores
(tbl.contacts)
| Companyname | CountryID
and the second table (tbl_geo_country)
| ID | Countrycode | Name |
Now I want to create a report that can show me how many customers are from what country. example output
| Country | QNT |
Norway 5
USA 3
Sweden 2
I dont know how many different countries it has stored so it also needs to check that.
Seems like a JOIN and GROUP BY to me:
SELECT country.Name, COUNT(contact.ID) as QNT
FROM tbl_geo_country country
INNER JOIN tbl.contacts contact ON country.ID = contact.CountryID
GROUP BY country.Name
ORDER BY COUNT(contact.ID)
Keep in mind that this would return only countries, that have at least one contact. If you also need countries that have no contacts, you need to change INNER JOIN to LEFT JOIN.
I've been approaching a problem perhaps in the wrong way. I've researched pivot examples
http://www.codeproject.com/Tips/500811/Simple-Way-To-Use-Pivot-In-SQL-Query
How to create a pivot query in sql server without aggregate function
but they aren't the type I'm looking for.. or perhaps I'm approaching this in the wrong way, and I'm new to sql server.
I want to transform:
Student:
studid | firstname | lastname | school
-----------------------------------------
1 mike lee harvard
1 mike lee ucdavis
1 mike lee sfsu
2 peter pan chico
2 peter pan ulloa
3 peter smith ucb
Desired output: (note for school, want only 3 columns max.)
studid| firstname | lastname | school1 | school2 | school3
---------------------------------------------------------------------
1 mike lee Harvard ucdavis sfsu
2 peter pan chico ulloa
3 peter smith ucb
The tutorials I see shows the use of Sum() , count() ... but I have no idea how to pivot string values of one column and put them into three columns.
You can get the results you desire by taking max(school) for each pivot value. I'm guessing the pivot value you want is rank over school partitioned by student. This would be the query for that:
select * from
(select *, rank() over (partition by studid order by school) rank from student) r
pivot (max(school) for rank in ([1],[2],[3])) pv
note that max doesn't actually do anything. the query would return the same results if you replaced it with min. just the pivot syntax requires the use of an aggregate function here.
I'm new to designing cubes with SSAS.
In my simple cube, I have one fact table with 3 dimension tables, as below. The fact table (table1) contains a list of client IDs and other columns linking to the 3 dimensions. This all works fine.
table1
client_id | dimension_link_1 | dimension_link_2 | dimension_link_3
AAAAA | xxx |zzz |bbb
BBBBB | yyy |aaa |ccc
I have another table (table2) that contains three columns - Client ID, Classification Type and Classification Name. A client may have 1-n classifications recorded against them (i.e. ethnicity, religion, allergies etc) so the Client ID may appear on multiple rows in table2. e.g.
table2
client_id | classification_type | classification_name
AAAAA | Ethnicity | Japanese
AAAAA | Allergy | Hayfever
AAAAA | Nationality | Russian
BBBBB | Ethnicity | Spanish
BBBBB | Allergy | Aspirin
BBBBB | Nationality | Spanish
BBBBB | Physical Support | Yes
I want to add table2 into my cube so that I can aggregate the list of client IDs by the existing fact table (table1) by Classification Type and Classification Name in table2.
However, I'm not sure what the correct approach for doing this is? I tried joining table2 to the fact table (table1) as a dimension linked on Client ID but I think this only joined the two objects together using the first occurrence of the Client ID in table2.
Help! :)
Thanks,
Hologram
Import table2 as both a fact table and a dimension. Then in the cube designer in the dimension usage tab, when specifying the relationship between the measure group formed from table1 and the dimension formed from table2, choose "Many to Many" as the relationship type and ensure the "intermediate measure group" is the one you formed from table2.
Suppose I have this simple table
UserID|Name |Aid ID
1 |Bob | 3
2 |Alice | 1
3 |Ted | 4
4 |Sam | 2
In a query, I would have to list the name of the person, and the name of the person that they aid. I thought about doing a View, but I feel like this could be done in a simple query than creating a view. How would I do that, and how does the query work exactly, like the fundamentals behind it?
you need to join the table to itself
SELECT a."UserID",
a."Name",
b."Name" As AIDName
FROM tableName a
INNER JOIN tableName b
ON a."AidID" = b."UserID"
SQLFiddle Demo
Query will be
select persons.name,aid.name
from your_tablename as persons,
your_tablename as aid
where persons.aidid=aid.userID
I have a database table called A and now i have create a new table called B and create some columns of A in table B.
Eg: Suppose following columns in tables
Table A // The one already exists
Id, Country Age Firstname, Middlename, Lastname
Table B // The new table I create
Id Firstname Middlename Lastname
Now the table A will be look like,
Table A // new table A after the modification
Id, Country, Age, Name
In this case it will map with table B..
So my problem is now i need to kind of maintain the reports which were generated before the table modifications and my friend told me you need to have a data migration..so may i know what is data migration and how its work please.
Thank you.
Update
I forgot to address the reporting issue raised by the OP (Thanks Mark Bannister). Here is a stab at how to deal with reporting.
In the beginning (before data migration) a report to generate the name, country and age of users would use the following SQL (more or less):
-- This query orders users by their Lastname
SELECT Lastname, Firstname, Age, Country FROM tableA order by Lastname;
The name related fields are no longer present in tableA post data migration. We will have to perform a join with tableB to get the information. The query now changes to:
SELECT b.Lastname, b.Firstname, a.Country, a.Age FROM tableA a, tableB b
WHERE a.name = b.id ORDER BY b.Lastname;
I don't know how exactly you generate your report but this is the essence of the changes you will have to make to get your reports working again.
Original Answer
Consider the situation when you had only one table (table A). A couple of rows in the table would look like this:
# Picture 1
# Table A
------------------------------------------------------
Id | Country | Age | Firstname | Middlename | Lastname
1 | US | 45 | John | Fuller | Doe
2 | UK | 32 | Jane | Margaret | Smith
After you add the second table (table B) the name related fields are moved from table A to table B. Table A will have a foreign key pointing to the table B corresponding to each row.
# Picture 2
# Table A
------------------------------------------------------
Id | Country | Age | Name
1 | US | 45 | 10
2 | UK | 32 | 11
# Table B
------------------------------------------------------
Id | Firstname | Middlename | Lastname
10 | John | Fuller | Doe
11 | Jane | Margaret | Smit
This is the final picture. The catch is that the data will not move from table A to table B on its own. Alas human intervention is required to accomplish this. If I were the said human I would follow the steps given below:
Create table B with columns Id, Firstname, Middlename and Lastname. You now have two tables A and B. A has all the existing data, B is empty .
Add a foreign key to table A. This FK will be called name and will reference the id field of table B.
For each row in table A create a new row in table B using the Firstname, Middlename and Lastname fields taken from table A.
After copying each row, update the name field of table A with the id of the newly created row in table B.
The database now looks like this:
# Table A
-------------------------------------------------------------
Id | Country | Age | Firstname | Middlename | Lastname | Name
1 | US | 45 | John | Fuller | Doe | 10
2 | UK | 32 | Jane | Margaret | Smith | 11
# Table B
------------------------------------------------------
Id | Firstname | Middlename | Lastname
10 | John | Fuller | Doe
11 | Jane | Margaret | Smith
Now you no longer need the Firstname, Middlename and Lastname columns in table A so you can drop them.
voilà, you have performed a data migration!
The process I just described above is but a specific example of a data migration. You can accomplish it in a number of ways using a number of languages/tools. The choice of mechanism will vary from case to case.
Maintenance of the existing reports will depend on the tools used to write / generate those reports. In general:
Identify the existing reports that used table A. (Possibly by searching for files that have the name of table A inside them - however, if table A has a name [eg. Username] which is commonly used elsewhere in the system, this could return a lot of false positives.)
Identify which of those reports used the columns that have been removed from table A.
Amend the existing reports to return the moved columns from table B instead of table A.
A quick way to achieve this is to create a database view that mimics the old structure of table A, and amend the affected reports to use the database view instead of table A. However, this adds an extra layer of complexity into maintaining the reports (since developers may need to maintain the database view as well as the reports) and may be deprecated or even blocked by the DBAs - consequently, I would only recommend using this approach if a lot of existing reports are affected.