I have a problem with a t-sql query.
Let's say I have a categories tree (categories ID)
cat_table
1
|
2-\
| 3-\
6 | 5
| 4 |
... ...
ads_table
ad_ID
category_ID
of course the category_ID column references to the ID column in the cat_table
the problem is, how to get (recursive ?) all advertisements from all categories which the top-most parent is the 1st category?
try using a recursive Common Table Expressions, aka "CTE" (available in SQL Server 2005 and up) like this:
--go through a nested table supervisor - user table and display the chain
DECLARE #Contacts table (id varchar(6), first_name varchar(10), reports_to_id varchar(6))
INSERT #Contacts VALUES ('1','Jerome', NULL ) -- tree is as follows:
INSERT #Contacts VALUES ('2','Joe' ,'1') -- 1-Jerome
INSERT #Contacts VALUES ('3','Paul' ,'2') -- / \
INSERT #Contacts VALUES ('4','Jack' ,'3') -- 2-Joe 9-Bill
INSERT #Contacts VALUES ('5','Daniel','3') -- / \ \
INSERT #Contacts VALUES ('6','David' ,'2') -- 3-Paul 6-David 10-Sam
INSERT #Contacts VALUES ('7','Ian' ,'6') -- / \ / \
INSERT #Contacts VALUES ('8','Helen' ,'6') -- 4-Jack 5-Daniel 7-Ian 8-Helen
INSERT #Contacts VALUES ('9','Bill ' ,'1') --
INSERT #Contacts VALUES ('10','Sam' ,'9') --
DECLARE #Root_id char(4)
--get 2 and below
SET #Root_id=2
PRINT '#Root_id='+COALESCE(''''+#Root_id+'''','null')
;WITH StaffTree AS
(
SELECT
c.id, c.first_name, c.reports_to_id, c.reports_to_id as Manager_id, cc.first_name AS Manager_first_name, 1 AS LevelOf
FROM #Contacts c
LEFT OUTER JOIN #Contacts cc ON c.reports_to_id=cc.id
WHERE c.id=#Root_id OR (#Root_id IS NULL AND c.reports_to_id IS NULL)
UNION ALL
SELECT
s.id, s.first_name, s.reports_to_id, t.id, t.first_name, t.LevelOf+1
FROM StaffTree t
INNER JOIN #Contacts s ON t.id=s.reports_to_id
WHERE s.reports_to_id=#Root_id OR #Root_id IS NULL OR t.LevelOf>1
)
SELECT * FROM StaffTree
output:
#Root_id='2 '
id first_name reports_to_id Manager_id Manager_first_name LevelOf
------ ---------- ------------- ---------- ------------------ -----------
2 Joe 1 1 Jerome 1
3 Paul 2 2 Joe 2
6 David 2 2 Joe 2
7 Ian 6 6 David 3
8 Helen 6 6 David 3
4 Jack 3 3 Paul 3
5 Daniel 3 3 Paul 3
(7 row(s) affected)
change #Root_id to get different output:
#Root_id=null
id first_name reports_to_id Manager_id Manager_first_name LevelOf
------ ---------- ------------- ---------- ------------------ -----------
1 Jerome NULL NULL NULL 1
2 Joe 1 1 Jerome 2
9 Bill 1 1 Jerome 2
10 Sam 9 9 Bill 3
3 Paul 2 2 Joe 3
6 David 2 2 Joe 3
7 Ian 6 6 David 4
8 Helen 6 6 David 4
4 Jack 3 3 Paul 4
5 Daniel 3 3 Paul 4
(10 row(s) affected)
There is an option to avoid recurrency in tree browsing queries. You can add 'Path' column to your categories tree. It should contain each element ancestors IDs delimited with some non-numeric character (like slash).
For example your "ID=4" category's path would look like that: "/1/2/3/"
Now when you join your ads table to categories you need to do following:
select * from ads_table
inner join cat_table on cat_table.ID = ads_table.category_ID
where cat_table.Path like '/1/%'
And that's your query.
You can read more on this topic on my blog post
Are you familiar with Common Table Expressions in SQL Server? One of the many uses a CTE has is to do recursive queries.
The following is one of the best articles I've found on the subject:
https://web.archive.org/web/20210927200924/http://www.4guysfromrolla.com/webtech/071906-1.shtml
Related
Before, I had to solve something similar:
Here was my pivot and flatten for another solution:
I want to do the same thing on the example below but it is slightly different because there are no ranks.
In my previous example, the table looked like this:
LocationID Code Rank
1 123 1
1 124 2
1 138 3
2 999 1
2 888 2
2 938 3
And I was able to use this function to properly get my rows in a single column.
-- Check if tables exist, delete if they do so that you can start fresh.
IF OBJECT_ID('tempdb.dbo.#tbl_Location_Taxonomy_Pivot_Table', 'U') IS NOT NULL
DROP TABLE #tbl_Location_Taxonomy_Pivot_Table;
IF OBJECT_ID('tbl_Location_Taxonomy_NPPES_Flattened', 'U') IS NOT NULL
DROP TABLE tbl_Location_Taxonomy_NPPES_Flattened;
-- Pivot the original table so that you have
SELECT *
INTO #tbl_Location_Taxonomy_Pivot_Table
FROM [MOAD].[dbo].[tbl_Location_Taxonomy_NPPES] tax
PIVOT (MAX(tax.tbl_lkp_Taxonomy_Seq)
FOR tax.Taxonomy_Rank in ([1],[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15])) AS pvt
-- ORDER BY Location_ID
-- Flatten the tables.
SELECT Location_ID
,max(piv.[1]) as Tax_Seq_1
,max(piv.[2]) as Tax_Seq_2
,max(piv.[3]) as Tax_Seq_3
,max(piv.[4]) as Tax_Seq_4
,max(piv.[5]) as Tax_Seq_5
,max(piv.[6]) as Tax_Seq_6
,max(piv.[7]) as Tax_Seq_7
,max(piv.[8]) as Tax_Seq_8
,max(piv.[9]) as Tax_Seq_9
,max(piv.[10]) as Tax_Seq_10
,max(piv.[11]) as Tax_Seq_11
,max(piv.[12]) as Tax_Seq_12
,max(piv.[13]) as Tax_Seq_13
,max(piv.[14]) as Tax_Seq_14
,max(piv.[15]) as Tax_Seq_15
-- JOIN HERE
INTO tbl_Location_Taxonomy_NPPES_Flattened
FROM #tbl_Location_Taxonomy_Pivot_Table piv
GROUP BY Location_ID
So, then here is the data I would like to work with in this example.
LocationID Foreign Key
2 2
2 670
2 2902
2 5389
3 3
3 722
3 2905
3 5561
So I have some data that is formatted like this:
I have used pivot on data like this before--But the difference was it had a rank also. Is there a way to get my foreign keys to show up in this format using a pivot?
locationID FK1 FK2 FK3 FK4
2 2 670 2902 5389
3 3 722 2905 5561
Another way I'm looking to solve this is like this:
Another way I could look at doing this is I have the values in:
this form as well:
LocationID Address_Seq
2 670, 5389, 2902, 2,
3 722, 5561, 2905, 3
etc
is there anyway I can get this to be the same?
ID Col1 Col2 Col3 Col4
2 670 5389, 2902, 2
This, adding a rank column and reversing the orders, should gives you what you require:
SELECT locationid, [4] col1, [3] col2, [2] col3, [1] col4
FROM
(
SELECT locationid, foreignkey,rank from #Pivot_Table ----- temp table with a rank column
) x
PIVOT (MAX(x.foreignkey)
FOR x.rank in ([4],[3],[2],[1]) ) pvt
Any help with the following would be much appreciated!
I have two tables: table1 is a summary table whilst table2 is a list of all data points. I want to be able to summarise the information in table2 for each row in table1.
table1:flip `grp`constraint!(`a`b`c`d; 10 10 20 20);
table2:flip `grp`cat`constraint`val!(`a`a`a`a`a`b`b`b;`cl1`cl1`cl1`cl2`cl2`cl2`cl2`cl1; 10 10 10 10 10 10 20 10; 1 2 3 4 5 6 7 8);
function:{[grpL;constraintL;catL] first exec total: sum val from table2 where constraint=constraintL, grp=grpL,cat=catL};
update cl1:function'[grp;constraint;`cl1], cl2:function'[grp;constraint;`cl2] from table1;
The fourth line of this code achieves what I want for the two categories:cl1 and cl2
In table1 I want to name a new column with the name of the category (cl1, cl2, etc.) and I want the values in that column to be the output from running the function over that column.
However, I have hundreds of different categories, so don't want to have to list them out manually as in the fourth line. How would I pass in a list of categories, e.g. below?
`cl1`cl2`cl3
Sticking to your approach, you would just have to make your update statement functional and then iterate over the columns like so:
{![`table1;();0b;(1#x)!enlist ((';function);`grp;`constraint;1#x)]} each `cl1`cl2
Assuming you can amend table1 in place. If you must retain the original table1 then you can pass it by value though it will consume more memory
{![x;();0b;(1#y)!enlist ((';function);`grp;`constraint;1#y)]}/[table1;`cl1`cl2]
Another approach would be to aggregate, pivot and join though it's not necessarily a better solution as you get nulls rather than zeros
a:select sum val by cat,grp,constraint from table2
p:exec (exec distinct cat from a)#cat!val by grp,constraint from a
table1 lj p
There are several different methods you can look into.
The easiest method would be a functional update - http://code.kx.com/wiki/JB:QforMortals2/queries_q_sql#Functional_update
Below, though, should somewhat prove more useful, quicker and neater:
Your problem can be split into 2 parts. For the first part, you are looking to create a sum of each category by grp and constraint within table2. As for the second part, you are looking to join these results (the lookups) onto the corresponding records from table1.
You can create the necessary groups using by
q)exec val,cat by grp,constraint from table2
grp constraint| val cat
--------------| ------------------------------
a 10 | 1 2 3 4 5 `cl1`cl1`cl1`cl2`cl2
b 10 | 6 8 `cl2`cl1
b 20 | ,7 ,`cl2
Note though, this will only create nested lists of the columns in your select query
Next is to sum each of the cat groups
q)exec sum each val group cat by grp,constraint from table2
grp constraint|
--------------| ------------
a 10 | `cl1`cl2!6 9
b 10 | `cl2`cl1!6 8
b 20 | (,`cl2)!,7
Then, to create the cat's columns you can use a pivot like syntax - http://code.kx.com/wiki/Pivot
q)cats:asc exec distinct cat from table2
q)exec cats#sum each val group cat by grp,constraint from table2
grp constraint| cl1 cl2
--------------| -------
a 10 | 6 9
b 10 | 8 6
b 20 | 7
Now you can use this lookup table and index into each row from table1
q)(exec cats#sum each val group cat by grp,constraint from table2)[table1]
cl1 cl2
-------
6 9
8 6
To fill the nulls with zeros, use the carat symbol - http://code.kx.com/wiki/Reference/Caret
q)0^(exec cats#sum each val group cat by grp,constraint from table2)[table1]
cl1 cl2
-------
6 9
8 6
0 0
0 0
And now you can join on each row from table1 to your results using join-each
q)table1,'0^(exec cats#sum each val group cat by grp,constraint from table2)[table1]
grp constraint cl1 cl2
----------------------
a 10 6 9
b 10 8 6
c 20 0 0
d 20 0 0
HTH, Sean
This approach is the easiest way to pass in a list of categories
{table1^flip x!function'[table1`grp;table1`constraint;]each x}`cl1`cl2
I have a table with answers regarding different questions, all of them numbered. There are basically these columns: IdAnswer (unique for each answer in the table), IdUser (which won't repeat even if the same user answer questions a second time), IdQuestion and Answer.
IdAnswer IdUser IdQuestion Answer
1 John 1 0
2 John 4 1
3 John 5 1
4 John 6 0
5 Bob 1 1
6 Bob 3 1
7 Bob 5 0
8 Mark 2 0
9 Mark 7 1
10 Mark 5 0
I'd like to select from this table all answers to a specific question (say, IdQuestion = 5), and also the last question each user answered just before question number 5.
In the end I need a table that should look like this:
IdAnswer IdUser IdQuestion Answer
2 John 4 1
3 John 5 1
6 Bob 3 1
7 Bob 5 0
9 Mark 7 1
10 Mark 5 0
I've managed to make this work using a cursor to iterate through each line from the first SELECT result (which filters by IdQuestion), but I'm not sure if this is the best (and fastest) way of doing it. Is there any more efficient way of achieving the same result?
And by the way, I'm using SQL Server Management Studio 2012.
Here is one way using LEAD function
select * from
(
select *,NextQ = Lead(IdQuestion)over(partition by IdUser order by IdAnswer)
from youtable
) a
Where 5 in (IdQuestion, NextQ )
for older versions
;WITH cte
AS (SELECT prev_id = Min(CASE WHEN IdQuestion = 5 THEN rn - 1 END) OVER( partition BY IdUser),*
FROM (SELECT rn = Row_number()OVER(partition BY IdUser ORDER BY IdAnswer),*
FROM Yourtable)a)
SELECT *
FROM cte
WHERE rn IN ( prev_id, prev_id + 1 )
I have two tables:
PeriodId Period (Periods Table)
-------- -------
1 Week 1
2 Week 2
3 Week 3
EmpId PeriodId ApprovedDate (Worked Table)
----- -------- ------------
1 1 Null
1 2 2/28/2013
2 2 2/28/2013
I am trying to write a query that results in this:
EmpId Period Worked ApprovedDate
----- -------- --------- ------------
1 Week 1 Yes Null
1 Week 2 Yes 2/28/2013
1 Week 3 No Null
2 Week 1 No Null
2 Week 2 Yes 2/28/2013
2 Week 3 No Null
The idea is that I need each Period from the Periods table for each Emp. If there was no record in the Worked table then the 'No' value is placed Worked field.
What does the TSQL look like to get this result?
(Note: if it helps I also have access to an Employee table that has EmpId and LastName for each employee. For performance reasons I'm hoping not to need this but if I do then so be it.)
You should be able to use the following:
select p.empid,
p.period,
case
when w.PeriodId is not null
then 'Yes'
else 'No' End Worked,
w.ApprovedDate
from
(
select p.periodid, p.period, e.empid
from periods p
cross join (select distinct EmpId from worked) e
) p
left join worked w
on p.periodid = w.periodid
and p.empid = w.empid
order by p.empid
See SQL Fiddle with Demo
my table look like this..
id name count
-- ---- -----
1 Mike 0
2 Duke 2
3 Smith 1
4 Dave 6
5 Rich 3
6 Rozie 8
7 Romeo 0
8 Khan 1
----------------------
I want to select rows with max(count) limit 5 (TOP 5 Names with maximum count)
that would look sumthing like...
id name count
-- ---- -----
6 Rozie 8
4 Dave 6
5 Rich 3
2 Duke 2
3 Smith 1
please help,,
thanks
Here is how:
MySQL:
SELECT * FROM tableName ORDER BY count DESC LIMIT 5
MS SQL:
SELECT TOP 5 * FROM tableName ORDER BY count DESC