The problem is following:
I have to retrieve and sort records which are logically separated in two groups: Active (2,1) and Inactive (0).
The problem is that Active group consists of two values, the Inactive of one value and sorting has to be applied to logical groups not field values.
E.g.
Product Product_Description Status Priority
"Soap" "Nice soap" 2 A
"Sponge" "Hard sponge" 1 B
"Water" "It comes there too" 0 A
"Wind" "I don't know how it got here" 0 B
"Toothbrush" "It's more logical" 2 B
So the query should order records by Status and Priority. But the Status column consists of 3 values separated logically in two groups (2,1) and (0).
Query should return:
"Soap" 2 A
"Toothbrush" 2 B
"Sponge" 1 B
"Water" 0 A
"Wind" 0 B
I cannot change table structure
The only idea which came to mind is by using Union all and dividing the query into two parts. But maybe there is a nicer way.
Thank you.
If you want to group 2 and 1 together, separate from 0 you can use
order by sign(status), priority
Related
Say I have two related sheets/tabs within a google sheet. One sheet/tab is titled "Categories", the other is "Measures".
Categories:
userid
catcode
1
a
1
b
2
a
3
c
Measures:
userid
catcode
points
1
a
5
1
b
5
1
c
3
2
a
4
3
c
3
For each user I'd like to be able to sum the points from the Measures table where the catcode is present for the user in the categories table. Ideally using an auto-extending/filling formula (like an arrayformula or query).
I have some idea how I'd approach this with SQL statements (joining the related tables, or doing a select where exists), but I'm new to googlesheets and would appreciate some direction here. I've experimented with this a bit and assuming a third table named "Users" with userids in column A, I can add this formula:
=sum(filter(measure!C2:C4, measure!A2:A4=users!A2, not(iserror(vlookup(measure!B2:B4, unique(filter(categories!B2:B5, categories!A2:A5=users!A2)), 1, false)))))
However this approach doesn't seem to be compatible with arrayformula and won't allow me to autofill down the Users tab for newly added userids. Sum itself is apparently incompatible with arrayformula. Additionally, if I enclose the above in arrayformula and replace sum with sumproduct or some other approach to the summation, I'm unable to get the users!A2 references to extend down as I'd expect via something like users!A2:A.
Any help/direction would be appreciated. Thanks!
Try:
=ARRAYFORMULA(QUERY({A1:A, VLOOKUP(A1:A&B1:B, {D1:D&E1:E, F1:F}, 2, 0)},
"select Col1,sum(Col2) where Col1 is not null group by Col1 label sum(Col2)''"))
I accepted a new feature to re-order some items by using Drag-and-Drop UI and save the preference for each user to the database. What's the best way to do so?
After reading some questions on StackOverflow, I found this solution.
Solution 1: Use decimal numbers to indicate order
For example,
id item order
1 a 1
2 b 2
3 c 3
4 d 4
If I insert item 4 between item 1 and 2, the order becomes,
id item order
1 a 1
4 d 1.5
2 b 2
3 c 3
In this way, every new order = order[i-1] + order[i+1] / 2
If I need to save the preference for every user, then I need to another relationship table like this,
user_id item_id order
1 1 1
1 2 2
1 3 3
1 4 1.5
I need num_of_users * num_of_items records to save this preference.
However, there's a solution I can think of.
Solution 2: Save the order preference in a column in the User table
This is straightforward by adding a column in the User table to record the order. Each value would be parsed as an array of item_ids that ranked by the index of the array.
user_id . item_order
1 [1,4,2,3]
2 [1,2,3,4]
Is there any limitation of this solution? Or is there any other ways to solve this problem?
Usually, an explicit ordering deals with the presentation or some specific processing of data. Hence, it's a good idea to separate entities of theirs presentation/processing. For example
users
-----
user_id (PK)
user_login
...
user_lists
----------
list_id, user_id (PK)
item_index
item_index can be a simply integer value :
ordered continuously (1,2...N): DELETE/INSERT of the whole list are normally required to change the order
ordered discretely with some seed (10,20...N): you can insert new items without reordering the whole list
Another reason to separate entity data and lists: reordering lists should be done in transaction that may lead to row/table locks. In case of separated tables only data in list table is impacted.
I have some data that relates to some production inputs and outputs.
What I want to do is, for each production run, show what went in and what came out.
I have, at this point, something that looks like this:
Run# Item Input Output
1 X 1
Y 1
2 A 2
B 3 2
C 3
Where Input/Output is derived from a 'direction' column group, and there are row groups on Run# and Item.
What I want is something like this:
Run# Item Input Item Output
1 X 1 Y 1
2 A 2 B 2
B 3 C 3
Is this even possible? I feel like it should be, but as you can probably see from the title, I don't even know what to begin searching.
The way to do this is to add a rank() over the query like so:
dense_rank() OVER (Run#, Direction Order By ItemCode) as rank
You can then perform a row grouping by the rank field (you don't have to display the column), and add ItemCode as a column in the column grouping.
i have three tables
documents
attributes
attributevalues
documents can have many attributes
and these atributes have value in attributevalue table
what i want in single query get all documents and assigned atributes of relevant documents in row each row
(i assume every documents have same attributes assigned dont need complexity of diffrent attribues now)
for example
docid attvalue1 attvalue2
1 2 2
2 2 2
3 1 1
how can i do that in single query
Off the top if my head, I don't think you can do this without dynamic SQL.
The crux of the Entity-Attribute-Value (EAV) technique (which is what you are using) is to store columns as rows. What you want to do is convert those rows back to columns for the purpose of this query. Using PIVOT makes this possible. However, PIVOT requires knowing the number of rows that need to be converted to columns at the time the query is written. So assuming you are using EAV because you need flexible attributes/values, you won't know this information when you write the query.
So the solution would be to use dynamic SQL in conjunction with PIVOT. Did a quick search and this looks promising (didn't really read the whole thing):
http://www.simple-talk.com/community/blogs/andras/archive/2007/09/14/37265.aspx
For the record, I am not a fan of dynamic SQL and would recommend finding another approach to the larger problem (e.g. pivoting in application code).
If you know all the attributes (and their IDs) at design-time:
SELECT d.docid,
a1.attvalue AS attvalue1
a2.attvalue AS attvalue2
FROM documents d
JOIN attributevalues a1 ON d.docid = a1.docid
JOIN attributevalues a2 ON d.docid = a2.docid
WHERE a1.attrid = 1
AND a2.attrid = 2
If you don't, things get quite a bit messier and difficult to answer without knowing your schema.
lets make example
documents table's columns
docid,docname,createddate,createduser
and values
1 account.doc 10.10.2010 aeon
2 hr.doc 10.11.2010 aeon
atributes table's columns
attid,name,type
and values
1 subject string
2 recursive int
attributevalues table's columns
attvalueid,docid,attid,attvalue(sql_variant)
and values
1 1 1 "accounting doc"
1 1 2 0
1 2 1 "humen r doc"
1 2 2 1
and I want query result
docid,name,atribvalue1,atribvalue1,atribvalueN
1 account.doc "accounting doc" 0
2 hr.doc "humen r doc" 1
This is a simple and common scenario at work, and I'd appreciate some input.
Say I am generating a report for the owners of a pet show, and they want to know which of their customers have bought how many of each pet. In this scenario my only tools are SQL and something that outputs my query to a spreadsheet.
As the shop owner, I might expect reports in the form:
Customer Dog Cat Rabbit
1 2 3 0
2 0 1 1
3 1 2 0
4 0 0 1
And if one day I decided to stock Goldfish then the report should now come out as.
Customer Dog Cat Rabbit Goldfish
1 2 3 0 0
2 0 1 1 0
3 1 2 0 0
4 0 0 1 0
5 0 0 0 1
But as you probably know, to have a query which works this way would involve some form of dynamic code generation and would be harder to do.
The simplest query would work along the lines of:
Cross join Customers and Pets, Outer join Sales, Group, etc.
and generate:
Customer Pet Quantity
1 Dog 2
1 Cat 3
1 Rabbit 0
1 Goldfish 0
2 Dog 0
2 Cat 1
2 Rabbit 1
...etc
a) How would I explain to the shop owners that the report they want is 'harder' to generate? I'm not trying to say it's harder to read, but it is harder to write.
b) What is the name of the concept I am trying to explain to the customer (to aid with my Googling)?
The name of the concept is 'cross-tab' and can be accomplished in several ways.
MS Access has proprietary extensions to SQL to make this happen. SQL pre-2k5 has a CASE trick and 2k5 and later has PIVOT, but I think you still need to know what the columns will be.
Some databases indeed support some way of creating cross tables, but I think most need to know
the columns in advance, so you'd have to modify the SQL (and get a database that supports such an extension).
Another alternative is to create a program that will postprocess the second "easy" table to get your clients the cross table as output. This is probably easier and more generic than having to modify SQL or dynamically generate it.
And about a way to explain the problem... you could show them in an Excel how many steps are needed to get the desired result:
Source data (your second listing).
Select values from the pets column
Place each pet type found on a new column
Count values per each type per client
Fill the values
and then say that SQL gives you only the source data, so it's of course more work.
This concept is called pivoting
SQL assumes that your data is represented in terms of relations with fixed structure.
Like, equality is a binary relation, "customer has this many pets of this type" is a ternary relation and so on.
When you see this resultset:
Customer Pet Quantity
1 Dog 2
1 Cat 3
1 Rabbit 0
1 Goldfish 0
2 Dog 0
2 Cat 1
2 Rabbit 1
, it's actually a relation defined by all possible combinations of domain values being in this relation.
Like, a customer 1 (domain customers id's) has exactly 2 (domain positive numbers) pets of genus dog (domain pets).
We don't see rows like these in the resultset:
Customer Pet Quantity
1 Dog 3
Pete Wife 0.67
, because the first row is false (customer 1 doesn't have 3 items of dog, but 2), and the second row values are out of their domain scopes.
SQL paradigma implies that your relations are defined when you issue a query and each row returned defines the relation completely.
SQL Server 2005+ can map rows into columns (that is what you want), but you should know the number of columns when designing the query (not running).
As a rule, the reports you are trying to build are built with reporting software which knows how to translate relational SQL resultsets into nice looking human readable reports.
I have always called this pivoting, but that may not be the formal name.
Whatever it's called you can do almost all of this in plain SQL.
SELECT customer, count(*), sum(CASE WHEN pet='dog' THEN 1 ELSE 0 END) as dog, sum(case WHEN pet='cat' THEN 1 ELSE 0 END) as cast FROM customers join pets
Obviously what's missing is the dynamic columns. I don't know if this is possible in straight SQL, but it's certainly possible in a stored procedure to generate the query dynamically after first querying for a list of pets. The query is built into a string then that string is used to create a prepared statement.