[HELP]
Hi everyone,
I have this table with the following columns:
id
textID
value
1
1
Hedonic
2
1
Negative feelings
3
2
Hedonic
4
2
Negative feelings
5
2
Fun
6
2
Motivation
7
3
Enjoy
8
3
Hedonic
9
3
Fun
10
4
Negative feelings
11
4
Pain
And what I want to do is return the frequency of values associated with a given input value.
For example, given the value 'Hedonic', I want to return the count of values associated where 'hedonic' exists.
With the data from the table presented above, it should return the following table, for input 'Hedonic':
value
count
Hedonic
3
Negative feelings
2
Fun
2
Enjoy
1
Motivation
1
Can anyone help me?
I have no idea how to perform the SQL query... I've tried several approaches, but still no success.
Thank you very much
One method uses exists:
select value, count(*)
from t
where exists (select 1
from t t2
where t2.textid = t.textid and t2.value = 'Hedonic'
)
group by value;
I have a child table with a number of charact/value pairs for a given 'material' (MaterialID). Any material can have a number of charact values and may have several of the same name (see id's 2,3).
The table has a large number of records (8+ million). What I'm trying to do is find the materials that are the most similar to a supplied material. That is, when I supply a MaterialID, I would like an ordered list of the most similar other materials (those with the most matching charact/value pairs).
I've done some research but, I may be missing some key terms or just not conceptualizing the problem correctly.
Any hints as to how to go about this would be very much appreciated.
ID MaterialID Charact Value
1 1 ROT_DIR CCW
2 1 SPECIAL_FEATURE CATALOG_CP
3 1 SPECIAL_FEATURE CHROME
4 1 SCHEDULE 80
5 2 BEARING_TYPE SB
6 2 SCHEDULE 80
7 3 ROT_DIR CCW
8 3 SPECIAL_FEATURE CATALOG_HSB
9 3 BEARING_TYPE SP
10 4 NDE_STYLE W_FAN
11 4 BEARING_TYPE SB
12 4 ROT_DIR CW*
You can do this with a self join:
select t.materialid, count(*) as nummatches
from t join
t tmat
on t.Charact = tmat.Charact and t.value = tmat.value
where tmat.materialid = #MaterialId
group by t.materialid
order by nummatches desc;
Notes:
You might want to remove the specified material, by adding where t.MaterialId <> tmat.MaterialId to the where clause.
If you want all materials, then make the join a left join and move the where condition to the on clause.
If you want only one material with the most matches, use select top 1.
If you want all materials with the most matches when there are ties, use `select top (1) with ties.
I want to select each 5 rows to be unique and the select pattern applies for the rest of the result (i.e if the result contains 10 records I am expecting to have 2 set of 5 unique rows)
Example:
What I have:
1
1
5
3
4
5
2
4
2
3
Result I want to achieve:
1
2
3
4
5
1
2
3
4
5
I have tried and searched a lot but couldn't find anything close to what I want to achieve.
Assuming that you can somehow order the rows within the sets of 5:
SELECT t.Row % 5, t.Row FROM #T t
ORDER BY t.Row , t.Row % 5
We could probably get closer to the truth with more details about what your data looks like and what it is you're trying to actually do.
This will work with the sample of data you provided
SELECT DISTINCT(thevalue) FROM theresults
UNION ALL
SELECT DISTINCT(thevalue) FROM theresults
But it's unclear to me if it's really what you need.
For instance :
if your table/results returns 12 rows, do you still want 2x5 rows or do you want 2x6 rows ?
do you have always in your table/results the same rows in double ?
There's a lot more questions to rise and no hint about them in what you asked.
I have below given query which is working fine but I want to use "Not In" operator instead of "In" but its giving no results:
SELECT DISTINCT OrderProdDetails.Priority
FROM OrderProdDetails
WHERE (((OrderProdDetails.Priority) In (SELECT DISTINCT OrderProdDetails.Priority
FROM OrderProdDetails WHERE (((OrderProdDetails.OrdID)=[Forms]![UpdateOrder]![OdrID])))));
Desired Query:
SELECT DISTINCT OrderProdDetails.Priority
FROM OrderProdDetails
WHERE (((OrderProdDetails.Priority) Not In (SELECT DISTINCT OrderProdDetails.Priority
FROM OrderProdDetails WHERE (((OrderProdDetails.OrdID)=[Forms]![UpdateOrder]![OdrID])))));
Basically it is referencing a control on parent form and based on that in a subform I want to populate the priority numbers i.e 1,2,3 and if for that record 1 is entered I want to get only 2 and 3 as drop-down option.
ReocordID OrdID Brand Name Priority
2 1 Org 1 2
3 2 Org 2 1
4 1 Org 1 1
6 1 Org 1 3
7 3 Org 3 1
8 4 Org 1 1
9 5 Org 2 1
10 5 Org 2 2
11 6 Org 1 1
12 6 Org 2 2
If there is any other better approach for the same please suggest.
Thanks in advance for your help.
In all likelihood, your problem is that Priority can take on NULL values. In that case, NOT IN doesn't work as expected (although it does work technically). The usual advice is to always use NOT EXISTS with subqueries rather than NOT IN.
But, in your case, I would suggest conditional aggregation instead:
SELECT opd.Priority
FROM OrderProdDetails as opd
GROUP BY opd.Priority
HAVING SUM(IIF(opd.OrdID = [Forms]![UpdateOrder]![OdrID], 1, 0)) = 0;
The HAVING clause counts the number of times the forms OdrId is in the orders. The = 0 means it is never there. Plus, you no longer need a select distinct.
Thanks for your prompt answers however I figured out what the problem was and the answer to problem is.
SELECT DISTINCT OrderProdDetails.Priority
FROM OrderProdDetails
WHERE (((OrderProdDetails.Priority) Not In (SELECT OrderProdDetails.Priority
FROM OrderProdDetails WHERE (((OrderProdDetails.OrdID)=[Forms]![UpdateOrder]![OdrID])
and ((OrderProdDetails.Priority) Is not null) ))));
I realized that the problem was happening only to those where there was a null value in priority so I puth the check of not null and it worked fine.
Thanks
I have the following tables, the groups table which contains hierarchically ordered groups and group_member which stores which groups a user belongs to.
groups
---------
id
parent_id
name
group_member
---------
id
group_id
user_id
ID PARENT_ID NAME
---------------------------
1 NULL Cerebra
2 1 CATS
3 2 CATS 2.0
4 1 Cerepedia
5 4 Cerepedia 2.0
6 1 CMS
ID GROUP_ID USER_ID
---------------------------
1 1 3
2 1 4
3 1 5
4 2 7
5 2 6
6 4 6
7 5 12
8 4 9
9 1 10
I want to retrieve the visible groups for a given user. That it is to say groups a user belongs to and children of these groups. For example, with the above data:
USER VISIBLE_GROUPS
9 4, 5
3 1,2,4,5,6
12 5
I am getting these values using recursion and several database queries. But I would like to know if it is possible to do this with a single SQL query to improve my app performance. I am using MySQL.
Two things come to mind:
1 - You can repeatedly outer-join the table to itself to recursively walk up your tree, as in:
SELECT *
FROM
MY_GROUPS MG1
,MY_GROUPS MG2
,MY_GROUPS MG3
,MY_GROUPS MG4
,MY_GROUPS MG5
,MY_GROUP_MEMBERS MGM
WHERE MG1.PARENT_ID = MG2.UNIQID (+)
AND MG1.UNIQID = MGM.GROUP_ID (+)
AND MG2.PARENT_ID = MG3.UNIQID (+)
AND MG3.PARENT_ID = MG4.UNIQID (+)
AND MG4.PARENT_ID = MG5.UNIQID (+)
AND MGM.USER_ID = 9
That's gonna give you results like this:
UNIQID PARENT_ID NAME UNIQID_1 PARENT_ID_1 NAME_1 UNIQID_2 PARENT_ID_2 NAME_2 UNIQID_3 PARENT_ID_3 NAME_3 UNIQID_4 PARENT_ID_4 NAME_4 UNIQID_5 GROUP_ID USER_ID
4 2 Cerepedia 2 1 CATS 1 null Cerebra null null null null null null 8 4 9
The limit here is that you must add a new join for each "level" you want to walk up the tree. If your tree has less than, say, 20 levels, then you could probably get away with it by creating a view that showed 20 levels from every user.
2 - The only other approach that I know of is to create a recursive database function, and call that from code. You'll still have some lookup overhead that way (i.e., your # of queries will still be equal to the # of levels you are walking on the tree), but overall it should be faster since it's all taking place within the database.
I'm not sure about MySql, but in Oracle, such a function would be similar to this one (you'll have to change the table and field names; I'm just copying something I did in the past):
CREATE OR REPLACE FUNCTION GoUpLevel(WO_ID INTEGER, UPLEVEL INTEGER) RETURN INTEGER
IS
BEGIN
DECLARE
iResult INTEGER;
iParent INTEGER;
BEGIN
IF UPLEVEL <= 0 THEN
iResult := WO_ID;
ELSE
SELECT PARENT_ID
INTO iParent
FROM WOTREE
WHERE ID = WO_ID;
iResult := GoUpLevel(iParent,UPLEVEL-1); --recursive
END;
RETURN iResult;
EXCEPTION WHEN NO_DATA_FOUND THEN
RETURN NULL;
END;
END GoUpLevel;
/
Joe Cleko's books "SQL for Smarties" and "Trees and Hierarchies in SQL for Smarties" describe methods that avoid recursion entirely, by using nested sets. That complicates the updating, but makes other queries (that would normally need recursion) comparatively straightforward. There are some examples in this article written by Joe back in 1996.
I don't think that this can be accomplished without using recursion. You can accomplish it with with a single stored procedure using mySQL, but recursion is not allowed in stored procedures by default. This article has information about how to enable recursion. I'm not certain about how much impact this would have on performance verses the multiple query approach. mySQL may do some optimization of stored procedures, but otherwise I would expect the performance to be similar.
Didn't know if you had a Users table, so I get the list via the User_ID's stored in the Group_Member table...
SELECT GroupUsers.User_ID,
(
SELECT
STUFF((SELECT ',' +
Cast(Group_ID As Varchar(10))
FROM Group_Member Member (nolock)
WHERE Member.User_ID=GroupUsers.User_ID
FOR XML PATH('')),1,1,'')
) As Groups
FROM (SELECT User_ID FROM Group_Member GROUP BY User_ID) GroupUsers
That returns:
User_ID Groups
3 1
4 1
5 1
6 2,4
7 2
9 4
10 1
12 5
Which seems right according to the data in your table. But doesn't match up with your expected value list (e.g. User 9 is only in one group in your table data but you show it in the results as belonging to two)
EDIT: Dang. Just noticed that you're using MySQL. My solution was for SQL Server. Sorry.
-- Kevin Fairchild
There was already similar question raised.
Here is my answer (a bit edited):
I am not sure I understand correctly your question, but this could work My take on trees in SQL.
Linked post described method of storing tree in database -- PostgreSQL in that case -- but the method is clear enough, so it can be adopted easily for any database.
With this method you can easy update all the nodes depend on modified node K with about N simple SELECTs queries where N is distance of K from root node.
Good Luck!
I don't remember which SO question I found the link under, but this article on sitepoint.com (second page) shows another way of storing hierarchical trees in a table that makes it easy to find all child nodes, or the path to the top, things like that. Good explanation with example code.
PS. Newish to StackOverflow, is the above ok as an answer, or should it really have been a comment on the question since it's just a pointer to a different solution (not exactly answering the question itself)?
There's no way to do this in the SQL standard, but you can usually find vendor-specific extensions, e.g., CONNECT BY in Oracle.
UPDATE: As the comments point out, this was added in SQL 99.