I am having a hard time figuring out how to ask this question, so I'll just go straight to the example code. Let's say I have these tables:
create table Item
(
ItemId int identity(1,1),
Name nvarchar(256)
)
create table ItemSale
(
ItemSaleId int identity(1,1),
ItemId int,
Price decimal,
CategoryId tinyint
)
What I want to retrieve is the list of ItemSale records that are not in a given CategoryId. The complication, at least for me, is that if a record exists in ItemSale for a given Item, I do not want to see any records for that Item.
So if I have this data:
insert into Item(Name)
select N'Widget' union all
select N'Foo' union all
select N'Buzz'
insert into ItemSale(ItemId, Price, CategoryId)
select 1, 9.95, 1 union all
select 1, 19.95, 2 union all
select 3, 99.99, 3
And the CategoryId I want to filter out is 1, then I don't want to see any records for ItemId 1 ("Widget"). So, with that sample data, I would only see the ItemSale record for Item with ID 3.
I know that my solution will most likely involve some sort of NOT EXISTS OR LEFT JOIN but I'm struggling with how to filter out all records instead of just the specific record that matches my criteria. What am I missing?
SQLFiddle: http://sqlfiddle.com/#!3/79c58
I might be over simplifying your problem, but I think this would work:
SELECT *
FROM ItemSale i
WHERE NOT EXISTS
( SELECT 1
FROM ItemSale i2
WHERE i.ItemID = i2.ItemID
AND i2.CategoryID = 1
);
Example on SQL Fiddle
Related
I'm not very experienced with advance SQL queries, I'm familiar with basic statements and basic joins, currently trying to figure out how to write a query that seems to be out of my depth and I haven't been able to find a solution from google so far and I'm hoping somebody might be able to point me in the right direction.
The table I'm working with has an ID column, and a 'parent id' column.
I'm looking for all descendants of ID '1' - rows with a parent ID of '1', rows with a parent ID equal to any row's ID with a parent ID of '1' etc. Currently I've been doing this manually but there are hundreds of descendants so far and I feel like there's a way to put this into one query.
Any help would be appreciated, if this is unclear I can also try to clarify.
EDIT - I got it working with the following query:
with cteMappings as (
select map_id, parent_map_id, map_name
from admin_map
where map_id = '1'
union all
select a.map_id, a.parent_map_id, a.map_name
from admin_map a
inner join cteMappings m
on a.parent_map_id = m.map_id
)
select map_id, parent_map_id, map_name
from cteMappings
Sounds like it can be achieved by Common Table Expression:
DECLARE #temp TABLE (id INT IDENTITY(1, 1), parent_id INT);
INSERT #temp
SELECT NULL
UNION ALL
SELECT 1
UNION ALL
SELECT 2
UNION ALL
SELECT NULL
SELECT * FROM #temp
; WITH HierarchyTemp (id, parent_id, depth) AS (
SELECT id, parent_id, 0
FROM #temp
WHERE id = 1
UNION ALL
SELECT t.id, t.parent_id, ht.depth + 1
FROM #temp t
INNER JOIN HierarchyTemp ht ON ht.id = t.parent_id
)
SELECT *
FROM HierarchyTemp
So the above example is creating a table variable with 4 rows:
id parent_id
1 NULL
2 1
3 2
4 NULL
Result of descendent of id '1' (also including itself, but can be excluded with an additional WHERE clause):
id parent_id depth
1 NULL 0
2 1 1
3 2 2
I have 3 tables:
recipe:
id, name
ingredient:
id, name
recipeingredient:
id, recipeId, ingredientId, quantity
Every time, a customer creates a new recipe, I need to check the recipeingredient table to verify if this recipe exists or not. If ingredientId and quantity are exactly the same, I will tell the customer the recipe already exists. Since I need to check multiple rows, need help to write this query.
Knowing your ingredients and quantities, you can do something like this:
select recipeId as ExistingRecipeID
from recipeingredient
where (ingredientId = 1 and quantity = 1)
or (ingredientId = 8 and quantity = 1)
or (ingredientId = 13 and quantity = 1)
group by recipeId
having count(*) = 3 --must match # of ingeredients in WHERE clause
I originally thought that the following query would find pairs of recipes that have exactly the same ingredients:
select ri1.recipeId, ri2.recipeId
from RecipeIngredient ri1 full outer join
RecipeIngredient ri2
on ri1.ingredientId = ri2.ingredientId and
ri1.quantity = ri2.quantity and
ri1.recipeId < ri2.recipeId
group by ri1.recipeId, ri2.recipeId
having count(ri1.id) = count(ri2.id) and -- same number of ingredients
count(ri1.id) = count(*) and -- all r1 ingredients are present
count(*) = count(ri2.id) -- all r2 ingredents are present
However, this query doesn't count things correctly, because the mismatches don't have the right pairs of ids. Alas.
The following does do the correct comparison. It counts the ingredients in each recipe before the join, so this value can just be compared on all matching rows.
select ri1.recipeId, ri2.recipeId
from (select ri.*, COUNT(*) over (partition by recipeid) as numingredients
from #RecipeIngredient ri
) ri1 full outer join
(select ri.*, COUNT(*) over (partition by recipeid) as numingredients
from #RecipeIngredient ri
) ri2
on ri1.ingredientId = ri2.ingredientId and
ri1.quantity = ri2.quantity and
ri1.recipeId < ri2.recipeId
group by ri1.recipeId, ri2.recipeId
having max(ri1.numingredients) = max(ri2.numingredients) and
max(ri1.numingredients) = count(*)
The having clause guarantees that each recipe that the same number of ingredients, and that the number of matching ingredients is the total. This time, I've tested it on the following data:
insert into #recipeingredient select 1, 1, 1
insert into #recipeingredient select 1, 2, 10
insert into #recipeingredient select 2, 1, 1
insert into #recipeingredient select 2, 2, 10
insert into #recipeingredient select 2, 3, 10
insert into #recipeingredient select 3, 1, 1
insert into #recipeingredient select 4, 1, 1
insert into #recipeingredient select 4, 3, 10
insert into #recipeingredient select 5, 1, 1
insert into #recipeingredient select 5, 2, 10
If you have a new recipe, you can modify this query to just look for the recipe in one of the tables (say ri1) using an additional condition on the on clause.
If you place the ingredients in a temporary table, you can substitute one of these tables, say ri1, with the new table.
You might try something like this to find if you have a duplicate:
-- Setup test data
declare #recipeingredient table (
id int not null primary key identity
, recipeId int not null
, ingredientId int not null
, quantity int not null
)
insert into #recipeingredient select 1, 1, 1
insert into #recipeingredient select 1, 2, 10
insert into #recipeingredient select 2, 1, 1
insert into #recipeingredient select 2, 2, 10
-- Actual Query
if exists (
select *
from #recipeingredient old
full outer join #recipeingredient new
on old.recipeId != new.recipeId -- Different recipes
and old.ingredientId = new.ingredientId -- but same ingredients
and old.quantity = new.quantity -- and same quantities
where old.id is null -- Match not found
or new.id is null -- Match not found
)
begin
select cast(0 as bit) as IsDuplicateRecipe
end
else begin
select cast(1 as bit) as IsDuplicateRecipe
end
Since this is really only searching for a duplicate, you might want to substitute a temp table or pass a table variable for the "new" table. This way you wouldn't have to insert the new records before doing your search. You could also insert into the base tables, wrap the whole thing in a transaction and rollback based upon the results.
products purchased
--------------------------
bana
bana
bana
stra
kiwi
reward requirements table (related to a rewards table)
reward id, products
----------------------
1,bana
1,bana
1,bana
2,stra
2,bana
3,stra
4,cart
5,bana
5,bana
5,oliv
Can you help me with sql to get rewards
the products purchased qualifies for?
In the case above the reward ids would be:
1
2
3
If there is a better design that would make the solution easier I welcome those as well. I'm using product names for the sake of easier explaining, I hope. (I'll replace with product ids later)
This query will solve your problem.
select r.reward_id
from (
select reward_id, product, count(*) needed
from reward_requirements
group by reward_id, product
) r
left join (
select product, count(*) bought
from products_purchased
group by product
) p on r.product=p.product and p.bought >= r.needed
group by r.reward_id
having count(reward_id) = count(distinct p.product)
order by r.reward_id
To make your design better, you could redo the reward_requirements to have the columns (product, needed) instead of having to list it multiple times. It will also get rid of the first subquery.
With this schema:
CREATE TABLE product
(
product_id int IDENTITY
, name varchar(50)
)
CREATE TABLE requirement
(
requirement_id int IDENTITY
, product_id int
, quantity int
, reward_id int
)
CREATE TABLE reward
(
reward_id int IDENTITY
, reward varchar(50)
)
CREATE TABLE purchased
(
purchased_id int IDENTITY
, product_id int
, quantity int
)
Your query becomes:
SELECT requirement.reward_id
FROM requirement
LEFT JOIN purchased
ON purchased.product_id = requirement.product_id
AND purchased.quantity >= requirement.quantity
GROUP BY requirement.reward_id
HAVING COUNT(purchased.product_id) = COUNT(requirement.reward_id);
Here's a SQLFiddle to play around with: http://sqlfiddle.com/#!3/e93c9/7
Sorry about the title, not sure how to describe without example. I trying to implement faceting of attributes in SQL Server 2008.
I have 2 tables. itemAttributes and facetParameters
Assume the following values in itemAttributes
id, itemId, name, value
---------------------------------------
1 1 keywords example1
2 1 keywords example2
3 2 color red
4 2 keywords example1
5 2 keywords example2
6 3 keywords example2
7 3 color red
8 3 color blue
Assume the following values in facetParameters
name value
----------------------
keywords example1
color red
I need to retrieve the (optional: distinct) itemIds where a given itemId has rows that contain all the values in facetParameters.
e.g. given the rows in facetParameters the query should return itemId 2. At the moment I would be using this in a CTE however given that they do not support a number of features I can work around this if there is no solution that works inside a CTE.
I have done a fair bit of sql over the years but this one has really stumped me and the shame is I keep thinking the answer must be simple.
You could join both tables, and use a having clause to ensure that all items match:
select ia.itemid
from #itemAttributes ia
inner join #facetParameters fp
on ia.name = fp.name
and ia.value = fp.value
group by ia.itemid
having count(distinct fp.name) =
(
select count(*) from #facetParameters
)
The count in the having clause assumes that the name uniquely identifies a row in the facetParameters table. If it doesn't, add an identity column to facetParameters, and use count(distinct id_column) instead of count(distinct fp.name).
Here's code to create the data set in the question:
declare #itemAttributes table (id int, itemId int,
name varchar(max), value varchar(max))
insert into #itemAttributes
select 1,1,'keywords','example1'
union all select 2,1,'keywords','example2'
union all select 3,2,'color','red'
union all select 4,2,'keywords','example1'
union all select 5,2,'keywords','example2'
union all select 6,3,'keywords','example2'
union all select 7,3,'color','red'
union all select 8,3,'color','blue'
declare #facetParameters table (name varchar(max), value varchar(max))
insert into #facetParameters
select 'keywords','example1'
union all select 'color','red'
I have a products table that contains a FK for a category, the Categories table is created in a way that each category can have a parent category, example:
Computers
Processors
Intel
Pentium
Core 2 Duo
AMD
Athlon
I need to make a select query that if the selected category is Processors, it will return products that is in Intel, Pentium, Core 2 Duo, Amd, etc...
I thought about creating some sort of "cache" that will store all the categories in the hierarchy for every category in the db and include the "IN" in the where clause. Is this the best solution?
The best solution for this is at the database design stage. Your categories table needs to be a Nested Set. The article Managing Hierarchical Data in MySQL is not that MySQL specific (despite the title), and gives a great overview of the different methods of storing a hierarchy in a database table.
Executive Summary:
Nested Sets
Selects are easy for any depth
Inserts and deletes are hard
Standard parent_id based hierarchy
Selects are based on inner joins (so get hairy fast)
Inserts and deletes are easy
So based on your example, if your hierarchy table was a nested set your query would look something like this:
SELECT * FROM products
INNER JOIN categories ON categories.id = products.category_id
WHERE categories.lft > 2 and categories.rgt < 11
the 2 and 11 are the left and right respectively of the Processors record.
Looks like a job for a Common Table Expression.. something along the lines of:
with catCTE (catid, parentid)
as
(
select cat.catid, cat.catparentid from cat where cat.name = 'Processors'
UNION ALL
select cat.catid, cat.catparentid from cat inner join catCTE on cat.catparentid=catcte.catid
)
select distinct * from catCTE
That should select the category whose name is 'Processors' and any of it's descendents, should be able to use that in an IN clause to pull back the products.
I have done similar things in the past, first querying for the category ids, then querying for the products "IN" those categories. Getting the categories is the hard bit, and you have a few options:
If the level of nesting of categories is known or you can find an upper bound: Build a horrible-looking SELECT with lots of JOINs. This is fast, but ugly and you need to set a limit on the levels of the hierarchy.
If you have a relatively small number of total categories, query them all (just ids, parents), collect the ids of the ones you care about, and do a SELECT....IN for the products. This was the appropriate option for me.
Query up/down the hierarchy using a series of SELECTs. Simple, but relatively slow.
I believe recent versions of SQLServer have some support for recursive queries, but haven't used them myself.
Stored procedures can help if you don't want to do this app-side.
What you want to find is the transitive closure of the category "parent" relation. I suppose there's no limitation to the category hierarchy depth, so you can't formulate a single SQL query which finds all categories. What I would do (in pseudocode) is this:
categoriesSet = empty set
while new.size > 0:
new = select * from categories where parent in categoriesSet
categoriesSet = categoriesSet+new
So just keep on querying for children until no more are found. This behaves well in terms of speed unless you have a degenerated hierarchy (say, 1000 categories, each a child of another), or a large number of total categories. In the second case, you could always work with temporary tables to keep data transfer between your app and the database small.
Maybe something like:
select *
from products
where products.category_id IN
(select c2.category_id
from categories c1 inner join categories c2 on c1.category_id = c2.parent_id
where c1.category = 'Processors'
group by c2.category_id)
[EDIT] If the category depth is greater than one this would form your innermost query. I suspect that you could design a stored procedure that would drill down in the table until the ids returned by the inner query did not have children -- probably better to have an attribute that marks a category as a terminal node in the hierarchy -- then perform the outer query on those ids.
CREATE TABLE #categories (id INT NOT NULL, parentId INT, [name] NVARCHAR(100))
INSERT INTO #categories
SELECT 1, NULL, 'Computers'
UNION
SELECT 2, 1, 'Processors'
UNION
SELECT 3, 2, 'Intel'
UNION
SELECT 4, 2, 'AMD'
UNION
SELECT 5, 3, 'Pentium'
UNION
SELECT 6, 3, 'Core 2 Duo'
UNION
SELECT 7, 4, 'Athlon'
SELECT *
FROM #categories
DECLARE #id INT
SET #id = 2
; WITH r(id, parentid, [name]) AS (
SELECT id, parentid, [name]
FROM #categories c
WHERE id = #id
UNION ALL
SELECT c.id, c.parentid, c.[name]
FROM #categories c JOIN r ON c.parentid=r.id
)
SELECT *
FROM products
WHERE p.productd IN
(SELECT id
FROM r)
DROP TABLE #categories
The last part of the example isn't actually working if you're running it straight like this. Just remove the select from the products and substitute with a simple SELECT * FROM r
This should recurse down all the 'child' catagories starting from a given catagory.
DECLARE #startingCatagoryId int
DECLARE #current int
SET #startingCatagoryId = 13813 -- or whatever the CatagoryId is for 'Processors'
CREATE TABLE #CatagoriesToFindChildrenFor
(CatagoryId int)
CREATE TABLE #CatagoryTree
(CatagoryId int)
INSERT INTO #CatagoriesToFindChildrenFor VALUES (#startingCatagoryId)
WHILE (SELECT count(*) FROM #CatagoriesToFindChildrenFor) > 0
BEGIN
SET #current = (SELECT TOP 1 * FROM #CatagoriesToFindChildrenFor)
INSERT INTO #CatagoriesToFindChildrenFor
SELECT ID FROM Catagory WHERE ParentCatagoryId = #current AND Deleted = 0
INSERT INTO #CatagoryTree VALUES (#current)
DELETE #CatagoriesToFindChildrenFor WHERE CatagoryId = #current
END
SELECT * FROM #CatagoryTree ORDER BY CatagoryId
DROP TABLE #CatagoriesToFindChildrenFor
DROP TABLE #CatagoryTree
i like to use a stack temp table for hierarchal data.
here's a rough example -
-- create a categories table and fill it with 10 rows (with random parentIds)
CREATE TABLE Categories ( Id uniqueidentifier, ParentId uniqueidentifier )
GO
INSERT
INTO Categories
SELECT NEWID(),
NULL
GO
INSERT
INTO Categories
SELECT TOP(1)NEWID(),
Id
FROM Categories
ORDER BY Id
GO 9
DECLARE #lvl INT, -- holds onto the level as we move throught the hierarchy
#Id Uniqueidentifier -- the id of the current item in the stack
SET #lvl = 1
CREATE TABLE #stack (item UNIQUEIDENTIFIER, [lvl] INT)
-- we fill fill this table with the ids we want
CREATE TABLE #tmpCategories (Id UNIQUEIDENTIFIER)
-- for this example we’ll just select all the ids
-- if we want all the children of a specific parent we would include it’s id in
-- this where clause
INSERT INTO #stack SELECT Id, #lvl FROM Categories WHERE ParentId IS NULL
WHILE #lvl > 0
BEGIN -- begin 1
IF EXISTS ( SELECT * FROM #stack WHERE lvl = #lvl )
BEGIN -- begin 2
SELECT #Id = [item]
FROM #stack
WHERE lvl = #lvl
INSERT INTO #tmpCategories
SELECT #Id
DELETE FROM #stack
WHERE lvl = #lvl
AND item = #Id
INSERT INTO #stack
SELECT Id, #lvl + 1
FROM Categories
WHERE ParentId = #Id
IF ##ROWCOUNT > 0
BEGIN -- begin 3
SELECT #lvl = #lvl + 1
END -- end 3
END -- end 2
ELSE
SELECT #lvl = #lvl - 1
END -- end 1
DROP TABLE #stack
SELECT * FROM #tmpCategories
DROP TABLE #tmpCategories
DROP TABLE Categories
there is a good explanation here link text
My answer to another question from a couple days ago applies here... recursion in SQL
There are some methods in the book which I've linked which should cover your situation nicely.