This may be pretty simple but I'm finding it difficult to wrap my head around this.
Basically, I have 2 tables, a and b. 'b' contains a list of all possible items, and 'a' contains a row which links to an item in 'b', and also a parent number. i.e, to display the rows in a with their information I do something like this:
select a.field1, a.field2, b.description
from a inner join b on a.itemid = b.itemid
where a.parentnumber = #parentnumber
That sort of thing work sfine. But I also want a dropdown box to display all that items that are not listed for that parent account in a. How would I do this?
SELECT *
FROM b
WHERE itemid NOT IN
(
SELECT itemid
FROM a
WHERE a.parentnumber = #parentnumber
)
By using a left join to this subquery, you can give an alias and use this alias to perform a null-check. I prefer this approach because the alias, which contains the results of the subquery, can be used through the whole query.
SELECT *
FROM b
LEFT JOIN
(
SELECT itemid
FROM a
Where a.parentnumber = #parentnumber
) As Sub On b.itemid = sub.itemid
WHERE sub.itemid IS NULL
Related
I have a simply shop with php and I need to ignore some products in shop on manage page. How to possible to make ignore in SQL query?
Here is my query:
$query = "SELECT a.*,
a.user as puser,
a.id as pid,
b.date as date,
b.price as price,
b.job_id as job_id,
b.masterkey as masterkey
FROM table_shop a
INNER JOIN table_shop_s b ON a.id = b.buyid
WHERE b.payok = 1
ORDER BY buyid";
I need to ignore list with product_id = "3","4" from table table_shop_s in this query
WHERE b.payok = 1 AND tablename.product_id != 3 AND tablename.product_id != 4
Simply use NOT IN (to ignore specific pids), with AND logical condition. Use the following:
$query = "SELECT a.*,
a.user as puser,
a.id as pid,
b.date as date,
b.price as price,
b.job_id as job_id,
b.masterkey as masterkey
FROM table_shop a
INNER JOIN table_shop_s b ON a.id = b.buyid
WHERE b.payok = 1
AND a.id NOT IN (3,4)
ORDER BY buyid";
Other answer has noted you would probably use a "productid NOT IN (3,4)" which would work, but that would be a short-term fix. Extend the thinking a bit. 2 products now, but in the future you have more you want to hide / prevent? What then, change all your queries and miss something?
My suggestion would be to update your product table. Add a column such as ExcludeFlag and have it set to 1 or 0... 1 = Yes, Exclude, 0 = ok, leave it alone. Then join your shop detail table to products and exclude when this flag is set... Also, you only need to "As" columns when you are changing their result column name, Additionally, by doing A.*, you are already getting ALL columns from alias "a" table, do you really need to add the extra instances of "a.user as puser, a.id as pid" ?
something like
SELECT
a.*,
b.date,
b.price,
b.job_id,
b.masterkey
FROM
table_shop a
INNER JOIN table_shop_s b
ON a.id = b.buyid
AND b.payok = 1
INNER JOIN YourProductTable ypt
on b.ProductID = ypt.ProductID
AND ypt.ExcludeFlag = 0
ORDER BY
a.id
Notice the extra join and specifically including all those where the flag is NOT set.
Also, good practice to alias table names closer to context of purpose vs just "a" and "b" much like my example of long table YourProductTable aliased as ypt.
I also changed the order by to "a.id" since that is the primary table in your query and also, since a.id = b.buyid, it is the same key order anyhow and probably is indexed on your "a" table too. the table_shop_s table I would assume already has an index on (buyid), but might improve when you get a lot of records to be indexed on (buyid, payok) to better match your JOINING criteria on both parts.
In many-to-many table, how to find ID where all criteria are matched, but maybe one row matches one criterion and another row matches another criterion?
For example, let's say I have a table that maps shopping carts to products, and another table where the products are defined.
How can I find a shopping cart that has at least one one match for every criterion?
Criteria could be, for example, product.category like '%fruit%', product.category like '%vegetable%', etc.
Ultimately I want to get back a shopping cart ID (could be all of them, but in my specific case I am happy to get any matching ID) that has at least one of each match in it.
I am assuming a table named cart_per_product with fields cart,product, and a table named product with fields product,category.
select cart from cart_per_product c
where exists
(
select 1 from product p1 where p1.product=c.product and p1.category like N'%fruit%'
)
and exists
(
select 1 from product p2 where p2.product=c.product and p2.category like N'%vegetable%'
)
You can use ANY and ALL operators combined with outer joins. A simple sample on a M:N relation:
select p.name
from products p
where id_product = ALL -- all operator
( select pc.id_product
from categories c
left outer join product_category pc on pc.id_product = p.id_product and
pc.id_category = c.id_category
)
I think you can figure out the column names
select c.id
from cart c
join product p
on c.pID = p.ID
group by c.id
having count(distinct p.catID) = (select count(distinct p.catID) from product)
Generic approach that possibly isn't the most efficient:
with data as (
select *,
count(case when <match condition> then 1 end)
over (partition by cartid) as matches
from <cart inner join products ...>
)
select * from data
where matches > 0;
This question already has an answer here:
Closed 10 years ago.
Possible Duplicate:
How to get Sum from two tables?
I have three table first "products" second "items" third "sales"
The first and second tables have the same columns('code','quantity') but the third table has ('code','name') now I want sum quantity from first and second but want also want get name from third table which code is equal.
check my code
Select code, sum(qtd),name
from ( select a.code, a.qtd from product a
union all select b.code, b.qtd from items b
union all select c.name from sales c where b.code=c.code
)
group by code
first two giving me perfect values but third fiction giving error not showing also names.
Hum....
SELECT
sales.name,
(SELECT SUM(products.quantity) FROM products WHERE products.code = sales.code) as products.quantity,
(SELECT SUM(items.quantity) FROM items WHERE items.code = sales.code) as items_quantity,
FROM sales
When using UNION be sure that the columns you want to combine matches with each SELECT statement. The first two SELECT statement works fine because they have the same number of columns. The third one failed because it has only one column.
The following are basic rules for combining the result sets of two (or more) queries by using UNION:
The number and the order of the columns must be the same in all queries.
The data types must be compatible.
From your query, I think you want like this,
SELECT a.code, b.name, SUM(a.qtd) totalSUM
FROM product a
INNER JOIN sales b
ON a.code = b.code
GROUP BY a.code, b.name
UNION
SELECT a.code, b.name, SUM(a.qtd) totalSUM
FROM items a
INNER JOIN sales b
ON a.code = b.code
GROUP BY a.code, b.name
I think you want to do something like this, though it's not clear what the actual requirements are:
select code = t1.code ,
name = t2.name ,
qtd = t1.qtd
from ( select code = t.code ,
qtd = sum( t.qtd )
from ( select a.code, a.qtd from product a
union all select b.code, b.qtd from items b
) t
group by t.code
) t1
join sales t2 where t2.code = t1.code
Cheers!
OK, I have a single table with keys and values that I need to query and order from that looks somewhat like this:
Let's say I want to pull all distinct items (resource_no) that are in the webcategory of "dog" (and any other values) and order them by "order" in ascending order so that my result is this:
I can't figure out how to query my table to allow this...I have tried inner joins but they do not seem to work...can anyone help? Thanks!
Kind of tricky to read when it's all in separate rows n the same table, but this should do it for the values you have now. If you're thinking dynamic columns, you'll need to go database specific procedures.
SELECT a.RESOURCE_NO, a.value webcategory, b.value location
FROM resources a
LEFT JOIN resources b ON a.RESOURCE_NO=b.RESOURCE_NO AND b.key='location'
LEFT JOIN resources c ON a.RESOURCE_NO=c.RESOURCE_NO AND c.key='order'
WHERE a.key = 'webcategory' AND a.value='dog'
GROUP BY RESOURCE_NO
ORDER BY c.value
Demo here.
select resource_no
, 'dog'
, location
from YourTable
where webcategory = 'location'
and resource_no in
(
select resource_no
from YourTable
where webcategory = 'dog'
)
order by
location
I am trying to filter a single table (master) by the values in multiple other tables (filter1, filter2, filter3 ... filterN) using only joins.
I want the following rules to apply:
(A) If one or more rows exist in a filter table, then include only those rows from the master that match the values in the filter table.
(B) If no rows exist in a filter table, then ignore it and return all the rows from the master table.
(C) This solution should work for N filter tables in combination.
(D) Static SQL using JOIN syntax only, no Dynamic SQL.
I'm really trying to get rid of dynamic SQL wherever possible, and this is one of those places I truly think it's possible, but just can't quite figure it out. Note: I have solved this using Dynamic SQL already, and it was fairly easy, but not particularly efficient or elegant.
What I have tried:
Various INNER JOINS between master and filter tables - works for (A) but fails on (B) because the join removes all records from the master (left) side when the filter (right) side has no rows.
LEFT JOINS - Always returns all records from the master (left) side. This fails (A) when some filter tables have records and some do not.
What I really need:
It seems like what I need is to be able to INNER JOIN on each filter table that has 1 or more rows and LEFT JOIN (or not JOIN at all) on each filter table that is empty.
My question: How would I accomplish this without resorting to Dynamic SQL?
In SQL Server 2005+ you could try this:
WITH
filter1 AS (
SELECT DISTINCT
m.ID,
HasMatched = CASE WHEN f.ID IS NULL THEN 0 ELSE 1 END,
AllHasMatched = MAX(CASE WHEN f.ID IS NULL THEN 0 ELSE 1 END) OVER ()
FROM masterdata m
LEFT JOIN filtertable1 f ON join_condition
),
filter2 AS (
SELECT DISTINCT
m.ID,
HasMatched = CASE WHEN f.ID IS NULL THEN 0 ELSE 1 END,
AllHasMatched = MAX(CASE WHEN f.ID IS NULL THEN 0 ELSE 1 END) OVER ()
FROM masterdata m
LEFT JOIN filtertable2 f ON join_condition
),
…
SELECT m.*
FROM masterdata m
INNER JOIN filter1 f1 ON m.ID = f1.ID AND f1.HasMatched = f1.AllHasMatched
INNER JOIN filter2 f2 ON m.ID = f2.ID AND f2.HasMatched = f2.AllHasMatched
…
My understanding is, filter tables without any matches simply must not affect the resulting set. The output should only consist of those masterdata rows that have matched all the filters where matches have taken place.
SELECT *
FROM master_table mt
WHERE (0 = (select count(*) from filter_table_1)
OR mt.id IN (select id from filter_table_1)
AND (0 = (select count(*) from filter_table_2)
OR mt.id IN (select id from filter_table_2)
AND (0 = (select count(*) from filter_table_3)
OR mt.id IN (select id from filter_table_3)
Be warned that this could be inefficient in practice. Unless you have a specific reason to kill your existing, working, solution, I would keep it.
Do inner join to get results for (A) only and do left join to get results for (B) only (you will have to put something like this in the where clause: filterN.column is null) combine results from inner join and left join with UNION.
Left Outer Join - gives you the MISSING entries in master table ....
SELECT * FROM MASTER M
INNER JOIN APPRENTICE A ON A.PK = M.PK
LEFT OUTER JOIN FOREIGN F ON F.FK = M.PK
If FOREIGN has keys that is not a part of MASTER you will have "null columns" where the slots are missing
I think that is what you looking for ...
Mike
First off, it is impossible to have "N number of Joins" or "N number of filters" without resorting to dynamic SQL. The SQL language was not designed for dynamic determination of the entities against which you are querying.
Second, one way to accomplish what you want (but would be built dynamically) would be something along the lines of:
Select ...
From master
Where Exists (
Select 1
From filter_1
Where filter_1 = master.col1
Union All
Select 1
From ( Select 1 )
Where Not Exists (
Select 1
From filter_1
)
Intersect
Select 1
From filter_2
Where filter_2 = master.col2
Union All
Select 1
From ( Select 1 )
Where Not Exists (
Select 1
From filter_2
)
...
Intersect
Select 1
From filter_N
Where filter_N = master.colN
Union All
Select 1
From ( Select 1 )
Where Not Exists (
Select 1
From filter_N
)
)
I have previously posted a - now deleted - answer based on wrong assumptions on you problems.
But I think you could go for a solution where you split your initial search problem into a matter of constructing the set of ids from the master table, and then select the data joining on that set of ids. Here I naturally assume you have a kind of ID on your master table. The filter tables contains the filter values only. This could then be combined into the statement below, where each SELECT in the eligble subset provides a set of master ids, these are unioned to avoid duplicates and that set of ids are joined to the table with data.
SELECT * FROM tblData INNER JOIN
(
SELECT id FROM tblData td
INNER JOIN fa on fa.a = td.a
UNION
SELECT id FROM tblData td
INNER JOIN fb on fb.b = td.b
UNION
SELECT id FROM tblData td
INNER JOIN fc on fc.c = td.c
) eligible ON eligible.id = tblData.id
The test has been made against the tables and values shown below. These are just an appendix.
CREATE TABLE tblData (id int not null primary key identity(1,1), a varchar(40), b datetime, c int)
CREATE TABLE fa (a varchar(40) not null primary key)
CREATE TABLE fb (b datetime not null primary key)
CREATE TABLE fc (c int not null primary key)
Since you have filter tables, I am assuming that these tables are probably dynamically populated from a front-end. This would mean that you have these tables as #temp_table (or even a materialized table, doesn't matter really) in your script before filtering on the master data table.
Personally, I use the below code bit for filtering dynamically without using dynamic SQL.
SELECT *
FROM [masterdata] [m]
INNER JOIN
[filter_table_1] [f1]
ON
[m].[filter_column_1] = ISNULL(NULLIF([f1].[filter_column_1], ''), [m].[filter_column_1])
As you can see, the code NULLs the JOIN condition if the column value is a blank record in the filter table. However, the gist in this is that you will have to actively populate the column value to blank in case you do not have any filter records on which you want to curtail the total set of the master data. Once you have populated the filter table with a blank, the JOIN condition NULLs in those cases and instead joins on itself with the same column from the master data table. This should work for all the cases you mentioned in your question.
I have found this bit of code to be faster in terms of performance.
Hope this helps. Please let me know in the comments.