I have this Table , (sequence_No.) Field is null :
ID Name age sequence_No.
-- ----- --- ------------
1 sara 20
2 sara 20
3 sara 20
4 john 24
5 john 24
6 Hama 23
I want to Update it to this:
ID Name age sequence_No.
-- ----- --- ------------
1 sara 20 1
2 sara 20 2
3 sara 20 3
4 john 24 1
5 john 24 2
6 Hama 23 1
Which query can do that in mysql?
thank you
You can emulate ROW_NUMBER() using correlated subquery in mysql. The resulting table with sequential number will be join with the table itself and update the value of sequence_No using the generated numbers.
UPDATE tableName a
INNER JOIN
(
SELECT A.ID,
(
SELECT COUNT(*)
FROM tableName c
WHERE c.Name = a.Name AND
c.ID <= a.ID) AS sequence_No
FROM TableName a
) b ON a.ID = b.ID
SET a.sequence_No = b.sequence_No
SQLFiddle Demo
SELECT ID, Name, age, sequence_No
FROM
(
select ID,
Name,
age,
#sum := if(#nme = Name AND #acct = age, #sum ,0) + 1 sequence_No,
#nme := Name,
#acct := age
from TableName,
(select #nme := '', #sum := 0, #acct := '') vars
order by Name, age
) s
ORDER BY ID
Or you may use
SELECT
ID,
Name,
age,
(
CASE Name
WHEN #curType
THEN #curRow := #curRow + 1
ELSE #curRow := 1 AND #curType := Name END
) + 1 AS sequence_No
FROM student, (SELECT #curRow := 0, #curType := '') r
ORDER BY ID,NAME;
this would work though i have not tested yet you can use the same to update your table
Related
I'm trying to produce an SQL statement to SUM top 5 values within categories per userID to create an overall total. Is this possible and how do I achieve it? I can sum the top 5 per single category or ALL but struggling to see how I can SUM each separate category total together.
For example,
ID Cater Weight
--------------------------------
1 Cheese 10
2 Bacon 15
1 Cheese 5
2 Bacon 10
1 Cheese 22
2 Cheese 5
1 Bacon 10
1 Cheese 10
2 Cheese 5
1 Cheese 20
2 Bacon 10
1 Cheese 30
The results i'm looking for is,
ID Total_Weight
-------------------
1 102 Top 5 Cheese (10+22+10+20+30) + Top 5 Bacon (10)
2 45 Top 5 Cheese (5+5) + Top 5 Bacon (15+10+10)
Any values outside of the Top 5 are ignored.
The code below displays the SUM of the top 5 weights from ALL categories AS total weight. Can I achieve what I want from a single statement?
$log = "SELECT id, cater,
SUM(weight) AS total_weight
FROM ( SELECT id,
CASE WHEN #ID = ID THEN #ROW_NUMBER := #ROW_NUMBER + 1
ELSE #ROW_NUMBER := 1
END AS rn,
cater,
weight,
#id := id
FROM individual,
(SELECT #ROW_NUMBER := 1, #ID := '') r
ORDER
BY
id, weight DESC
) TMP
WHERE rn <= 5
AND cater <> ''
GROUP
BY id
ORDER
BY total_weight DESC";
There might have some other better solution. But this will provide your expected result-
SELECT B.id,
SUM(T_weight) Total_Weight,
group_concat(concat('TOP 5 ',B.cater,' (',B.T,')') SEPARATOR ' ') Details
FROM
(
SELECT ID,cater,SUM(Weight) T_weight,group_concat(weight SEPARATOR '+') T
FROM
(
SELECT * FROM
(
SELECT id,cater, CASE WHEN #ID = ID THEN #ROW_NUMBER := #ROW_NUMBER + 1 ELSE #ROW_NUMBER := 1 END AS rn,weight,#id := id
FROM your_table,(SELECT #ROW_NUMBER := 1, #ID := ''
) r
WHERE cater = 'Cheese' ORDER BY id, weight DESC
)A WHERE rn < 6
UNION ALL
SELECT * FROM
(
SELECT id,cater, CASE WHEN #ID = ID THEN #ROW_NUMBER := #ROW_NUMBER + 1 ELSE #ROW_NUMBER := 1 END AS rn,weight,#id := id
FROM your_table,(SELECT #ROW_NUMBER := 1, #ID := ''
) r
WHERE cater = 'Bacon' ORDER BY id, weight DESC
)A WHERE rn < 6
UNION ALL
SELECT * FROM
(
SELECT id,cater, CASE WHEN #ID = ID THEN #ROW_NUMBER := #ROW_NUMBER + 1 ELSE #ROW_NUMBER := 1 END AS rn,weight,#id := id
FROM your_table,(SELECT #ROW_NUMBER := 1, #ID := ''
) r
WHERE cater = 'Cat3' ORDER BY id, weight DESC
)A WHERE rn < 6
UNION ALL
SELECT * FROM
(
SELECT id,cater, CASE WHEN #ID = ID THEN #ROW_NUMBER := #ROW_NUMBER + 1 ELSE #ROW_NUMBER := 1 END AS rn,weight,#id := id
FROM your_table,(SELECT #ROW_NUMBER := 1, #ID := ''
) r
WHERE cater = 'Cat4' ORDER BY id, weight DESC
)A WHERE rn < 6
UNION ALL
SELECT * FROM
(
SELECT id,cater, CASE WHEN #ID = ID THEN #ROW_NUMBER := #ROW_NUMBER + 1 ELSE #ROW_NUMBER := 1 END AS rn,weight,#id := id
FROM your_table,(SELECT #ROW_NUMBER := 1, #ID := ''
) r
WHERE cater = 'Cat5' ORDER BY id, weight DESC
)A WHERE rn < 6
UNION ALL
SELECT * FROM
(
SELECT id,cater, CASE WHEN #ID = ID THEN #ROW_NUMBER := #ROW_NUMBER + 1 ELSE #ROW_NUMBER := 1 END AS rn,weight,#id := id
FROM your_table,(SELECT #ROW_NUMBER := 1, #ID := ''
) r
WHERE cater = 'Cat6' ORDER BY id, weight DESC
)A WHERE rn < 6
)A
GROUP BY ID,Cater
)B
group by id
The output is-
1 191 TOP 5 Cheese (10+22+20+10+30) TOP 5 Cat3 (25+9+20+16+13) TOP 5 Bacon (10)
2 45 TOP 5 Cheese (5+5) TOP 5 Bacon (15+10+10)
If you have MySql version 8 or higher, you can use this code:
SELECT id, SUM (weight)
FROM (SELECT test.*,
ROW_NUMBER ()
OVER (PARTITION BY id, categ ORDER BY weight DESC)
rn
FROM test) sub
WHERE sub.rn < 6
GROUP BY id;
You need MySql 8+ because I used the function row_number and only from version 8 it exists.
In the below fiddle example, I used Microsoft Sql Server 2017 because they didn't had MySql 8 or higher.
You can see your example here.
I have a table
Id Name Id_collection Price
1 good1 2 10
2 good2 1 101
3 good3 3 102
4 good4 2 10
5 good5 2 10
I need to Group By id_collection, but i need to show 2 rows (to be able to change this value via variable or ... Ex: to change to 3 or 4 )
not
1
2
3
Ex
1
1
2
2
3
3
or
Ex
1
1
1
2
2
2
3
3
3
so the result must be
Id Name Id_collection Price
1 good1 2 10
4 good4 2 10
2 good2 1 101
3 good3 3 102
I was thinking about procedure or loop, but i didn't that before, Please help!!!
You want to group by adjacent values . . . in MySQL. You can use variables to assign the group. Alternatively, you can use this method to assign the group: count the number of rows that have id_collection different from each row with a smaller id.
You don't specify how to calculate the other columns, but here is a guess:
select min(id) as id, min(name) as name, id_collection, avg(price) as price
from (select t.*,
(select count(*)
from t t2
where t2.id_collection <> t.id_collection and
t2.id < t.id
) as grp
from t
) t
group by id_collection, grp;
EDIT:
I just realized that you probably don't want to aggregate the results; you probably just want the first row. For that, use variables:
select t.*
from (select t.*,
(#rn := if(#id = id_collection, #rn,
if(#id := id_collection, #rn + 1, #rn + 1)
)
) as rn
from t cross join
(select #id = -1, #rn := 0) params
order by id
) t
where rn = 1;
I edited a little the answer which #Gordon_Linoff posted, and it works now, you just have to change rn <= 3 this number and will get the various results.
#Gordon_Linoff - Thank you, this really helped me
select t.*
from (select t.*,
(#rn := if(#id = id_collection, #rn + 1,
if(#id := id_collection, 1, 0)
)
) as rn
from t cross join
(select #id := -1, #rn := 0) params
order by id_collection
) t
where rn <= 3;
Lets say I have the following table:
id coulmn_id value date
1 10 'a' 2016-04-01
1 11 'b' 2015-10-02
1 12 'a' 2016-07-03
1 13 'a' 2015-11-11
2 11 'c' 2016-01-10
2 23 'd' 2016-01-11
3 11 'c' 2016-01-09
3 111 'd' 2016-01-11
3 222 'c' 2016-01-10
3 333 'd' 2016-01-11
for n = 3, I want to get the latest n records<=3 for each id. So I will have the following output:
id column_id value date
1 10 'a' 2016-04-01
1 12 'a' 2016-07-03
1 13 'a' 2015-11-11
2 11 'c' 2016-01-10
2 23 'd' 2016-01-11
3 111 'd' 2016-01-11
3 222 'c' 2016-01-10
3 333 'd' 2016-01-11
I am answering because the referenced question has an unstable answer (I'll comment on that there).
Here is a solution that should work:
select t.*
from (select t.*,
(#rn := if(#id = id, #rn + 1,
if(#id := id, 1, 1)
)
) as seqnum
from t cross join
(select #rn := 0, #id := -1) params
order by id, date desc
) t
where seqnum <= 3;
The difference in the solutions is that the variable assignments are all in a single expression. MySQL does not guarantee the order of evaluation of expressions, so this is very important if the code is going to work consistently.
You could do this with the use of variables. First go through the results in reverse order and assign a row number, then filter the results for row numbers less or equal to 3, and re-order:
select id, value, date
from (
select id, value, date,
#rn := if(#id = id, #rn+1, if (#id := id, 1, 1)) rn
from mytable,
cross join (#id := null, #rn := null) init
order by id, date desc
) as base
where rn <= 3
order by id, date asc
It's possible to create a query that return the x/y number of records?
Eg.
I have table like this
ID | id_user | id_event
23 | 3 | 1
24 | 3 | 1
25 | 3 | 1
26 | 4 | 2
27 | 4 | 2
I will return something that looks like this:
Event
id_user 3 -> **1/3**
id_user 3 -> **2/3**
id_user 3 -> **3/3**
id_user 4 -> **1/2**
id_user 4 -> **2/2**
Any suggestion is appreciated!
Try this
SET #id_event := 0;
SELECT CONCAT('id_user ', id_user ,'->','**', (#id_event := #id_event + 1) ,'/', id_user ,** ) from table
This is probably a duplicate to this question.
SELECT CONCAT('id_user ',id_user,' -> **',rank,'/',group_total,'**') FROM (
SELECT id,
group_total,
CASE id_user
WHEN #id_user THEN
CASE id_event
WHEN #id_event THEN #rowno := #rowno + 1
ELSE #rowno := 1
END
ELSE #rowno :=1
END AS rank,
#id_user := id_user AS id_user,
#id_event := id_event AS id_event
FROM event_table
JOIN (SELECT id_user, id_event, COUNT(*) group_total FROM event_table GROUP BY id_user, id_event) t USING (id_user, id_event)
JOIN (SELECT #rowno := 0, #id_user := 0, #id_event := 0) r
ORDER BY id_user, id_event
) c;
Assuming you want output like this:
id_user < id_user > ** serial number of event related to this user / total events related to this user **
You can accomplish such result by the following query:
SELECT
CONCAT('id_user ',UE.id_user,' -> **',IF(#userID = UE.id_user, #eventNumber := #eventNumber + 1, #eventNumber := 1),'/',t.totalEvents,'**') AS output,
#userID := UE.id_user
FROM (SELECT #userID := -1, #eventNumber := 1) var,user_events UE
INNER JOIN
(
SELECT
id_user,
COUNT(id_event) totalEvents
FROM user_events
GROUP BY id_user
) AS t
ON UE.id_user = t.id_user
ORDER BY UE.id_user;
SQL FIDDLE DEMO
More:
SQL FIDDLE DEMO 2
This particular fiddle returns only the desired output column whereas the first fiddle contains one extra column
I played a little bit and that would be my solution:
SELECT id, id_user, id_event, if(#n = a.id_event, #c:=#c+1, if(#n:=a.id_event, #c:=1, #c:=1)) as count, (SELECT count(*) from TABLE b WHERE a.id_user = b.id_user) as total, from TABLE a join (SELECT #n:= "", #c:=1) c
It just have two if conditions for counting a #c up if #n and id_user matches if not #n become id_user and #c is 1 again. The join is for initialize the var in the same query.
Thx to that question, i found the answer to a questions that i asked 4 days ago.
I have a table that contains categories, dates and rates. Each category can have different rates for different dates, one category can have only one rate at a given date.
Id CatId Date Rate
------ ------ ------------ ---------
000001 12 2009-07-07 1
000002 12 2009-07-08 1
000003 12 2009-07-09 1
000004 12 2009-07-10 2
000005 12 2009-07-15 1
000006 12 2009-07-16 1
000007 13 2009-07-08 1
000008 13 2009-07-09 1
000009 14 2009-07-07 2
000010 14 2009-07-08 1
000010 14 2009-07-10 1
Unique index (catid, Date, Rate)
I would like for each category to group all continuous dates ranges and keep only the begin and the end of the range.
For the previous example, we would have:
CatId Begin End Rate
------ ------------ ------------ ---------
12 2009-07-07 2009-07-09 1
12 2009-07-10 2009-07-10 2
12 2009-07-15 2009-07-16 1
13 2009-07-08 2009-07-09 1
14 2009-07-07 2009-07-07 2
14 2009-07-08 2009-07-08 1
14 2009-07-10 2009-07-10 1
I found a similar solution in the forum which did not exactly give the result
WITH q AS
(
SELECT *,
ROW_NUMBER() OVER (PARTITION BY CatId, Rate ORDER BY [Date]) AS rnd,
ROW_NUMBER() OVER (PARTITION BY CatId ORDER BY [Date]) AS rn
FROM my_table
)
SELECT CatId AS catidd, MIN([Date]) as beginn, MAX([Date])as endd, Rate
FROM q
GROUP BY CatId, rnd - rn, Rate
SEE SQL FIDDLE
How can I do the same thing in mysql?
Please help!
MySQL doesn't support analytic functions, but you can emulate such behaviour with user-defined variables:
SELECT CatID, Begin, MAX(Date) AS End, Rate
FROM (
SELECT my_table.*,
#f:=CONVERT(
IF(#c<=>CatId AND #r<=>Rate AND DATEDIFF(Date, #d)=1, #f, Date), DATE
) AS Begin,
#c:=CatId, #d:=Date, #r:=Rate
FROM my_table JOIN (SELECT #c:=NULL) AS init
ORDER BY CatId, Rate, Date
) AS t
GROUP BY CatID, Begin, Rate
See it on sqlfiddle.
SELECT catid,min(ddate),max(ddate),rate
FROM (
SELECT
Catid,
Ddate,
rate,
#rn := CASE WHEN (#prev <> rate
or DATEDIFF(ddate, #prev_date)>1) THEN #rn+1 ELSE #rn END AS rn,
#prev := rate,
#prev_id := catid ,
#prev_date :=ddate
FROM (
SELECT CatID,Ddate,rate
FROM rankdate
ORDER BY CatID, Ddate ) AS a ,
(SELECT #prev := -1, #rn := 0, #prev_id:=0 ,#prev_date:=-1) AS vars
) T1 group by catid,rn
Note: The line (SELECT #prev := -1, #rn := 0, #prev_id:=0 ,#prev_date:=-1) AS vars is not necessary in Mysql Workspace, but it is in the PHP mysql_query function.
SQL FIDDLE HERE
I know I am late, still posting a solution that worked for me.
Had the same issue, here's how I got it
Found a good solution using variables
SELECT MIN(id) AS id, MIN(date) AS date, MIN(state) AS state, COUNT(*) cnt
FROM (
SELECT #r := #r + (#state != state OR #state IS NULL) AS gn,
#state := state AS sn,
s.id, s.date, s.state
FROM (
SELECT #r := 0,
#state := NULL
) vars,
t_range s
ORDER BY
date, state
) q
GROUP BY gn
More details at : https://explainextended.com/2009/07/24/mysql-grouping-continuous-ranges/