I have a table like this
UserID Score Date
5 6 2010-1-1
7 8 2010-1-2
5 4 2010-1-3
6 3 2010-1-4
7 4 2010-1-5
6 1 2010-1-6
I would like to get a table like this
UserID Score RunningTotal Date
5 6 6 2010-1-1
5 4 10 2010-1-3
6 3 3 2010-1-4
6 1 4 2010-1-6
7 8 8 2010-1-2
7 4 12 2010-1-5
Thanks!
Unlike Oracle, PostgreSQL and even MySQL, SQL Server has no efficient way to calculate running totals.
If you have few scores per UserID, you can use this:
SELECT userId,
(
SELECT SUM(score)
FROM scores si
WHERE si.UserID = so.UserID
AND si.rn <= so.rn
)
FROM (
SELECT *,
ROW_NUMBER() OVER (PARTITION BY UserID) AS rn
FROM scores
) so
, however, this will be very inefficient for larger tables.
For larger tables, you could benefit from using (God help me) a cursor.
Would something like this work for you...?
SELECT UserID, Score,
(SELECT SUM(Score)
FROM TableName innerTable
WHERE innerTable.UserID = outerTable.userID
AND innerTable.Date <= outerTable.date) AS RunningTotal
FROM TableName outerTable
This assumes, though, that a user cannot have more than one score per day. (What is your PK?)
Related
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 column like below : I have applied orderby percentileno Dec then it gives like below but I need proper order : 1,2,3,--10.
PercentileNo
1 (0.1-12.6)
10 (113.5-126)
2 (12.7-25.2)
3 (25.3-37.8)
4 (37.9-50.4)
5 (50.5-63)
6 (63.1-75.6)
7 (75.7-88.2)
8 (88.3-100.8)
9 (100.9-113.4)
I need order
1 (0.1-12.6)
2 (12.7-25.2)
3 (25.3-37.8)
4 (37.9-50.4)
5 (50.5-63)
6 (63.1-75.6)
7 (75.7-88.2)
8 (88.3-100.8)
9 (100.9-113.4)
10 (113.5-126)
Please help me Thanks in advance
Your question is not completely clear to me, but if you want to order your list you can do the following:
SELECT col_1, col_2
FROM table_1
ORDER BY col_1 DESC
So if you have a column called PercentileNo you could do:
SELECT PrecentileNo
FROM yourTable
ORDER BY PercentileNo DESC
Hope this helps.
I have the same problem as mentioned in In SQL, how to select the top 2 rows for each group. The answer is working fine. But it takes too much time. How to optimize this query?
Example:
sample_table
act_id: act_cnt:
1 1
2 1
3 1
4 1
5 1
6 3
7 3
8 3
9 4
a 4
b 4
c 4
d 4
e 4
Now i want to group it (or using some other ways). And i want to select 2 rows from each group. Sample Output:
act_id: act_cnt:
1 1
2 1
6 3
7 3
9 4
a 4
I am new to SQL. How to do it?
The answer you linked to uses an inefficient workaround for MySQL's lack of window functions.
Using a window function is most probably much faster as you only need to read the table once:
select name,
score
from (
select name,
score,
dense_rank() over (partition by name order by score desc) as rnk
from the_table
) t
where rnk <= 2;
SQLFiddle: http://sqlfiddle.com/#!15/b0198/1
Having an index on (name, score) should speed up this query.
Edit after the question (and the problem) has been changed
select act_id,
act_cnt
from (
select act_id,
act_cnt,
row_number() over (partition by act_cnt order by act_id) as rn
from sample_table
) t
where rn <= 2;
New SQLFiddle: http://sqlfiddle.com/#!15/fc44b/1
How can I add a series in length of 4 to a table like this:
Source table:
id
1
2
3
4
5
6
7
8
Results table:
id series
1 1
2 2
3 3
4 4
5 1
6 2
7 3
8 4
I'm using PostgreSQL 9.1.
If your IDs are really consecutive and gapless, you can just use id % 4 + 1. But I imagine that in reality your IDs aren't so orderly, and if they're generated from a SEQUENCE you shouldn't rely on them being gapless.
You can do it properly with row_number(), as shown here: http://sqlfiddle.com/#!12/22767/5
SELECT
id,
(row_number() OVER (ORDER BY id) - 1) % 4 + 1
FROM Table1
ORDER BY 1;
It's also possible to do using generate_series as a set-returning-function in the SELECT list, but that's a PostgreSQL extension, wheras the above is standard SQL that'll work in any modern database except MySQL, which doesn't support window functions.
If you want to actually add a column to the table it gets a bit more complicated. I'm not really sure why you'd want to do that, but it's possible using UPDATE ... FROM:
BEGIN;
ALTER TABLE table1 ADD COLUMN col2 INTEGER;
WITH gen_num(id,n) AS (
SELECT
id,
(row_number() OVER (ORDER BY id) - 1) % 4 + 1
FROM Table1
ORDER BY 1)
UPDATE table1 SET col2 = n
FROM gen_num
WHERE gen_num.id = table1.id;
COMMIT;
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Calculate a Running Total in SqlServer
I need to use values from previous row inorder to generate a cumulative value as shown below. Always for each Code for the year 2000 the starting Base is 100.
I need to ahieve this using tsql code.
id Code Yr Rate Base
1 4 2000 5 100
2 4 2001 7 107 (100+7)
3 4 2002 4 111 (107+4)
4 4 2003 8 119 (111+8)
5 4 2004 10 129 (119+10)
6 5 2000 2 100
7 5 2001 3 103 (100+3)
8 5 2002 8 111 (103+8)
9 5 2003 5 116 (111+5)
10 5 2004 4 120 (116+4)
OK. We have table like this
CREATE Table MyTbl(id INT PRIMARY KEY IDENTITY(1,1), Code INT, Yr INT, Rate INT)
And we would like to calculate cumulative value by Code.
So we can use query like this:
1) recursion (requires more resources, but outputs the result as in the example)
with cte as
(SELECT *, ROW_NUMBER()OVER(PARTITION BY Code ORDER BY Yr ASC) rn
FROM MyTbl),
recursion as
(SELECT id,Code,Yr,Rate,rn, CAST(NULL as int) as Tmp_base, CAST('100' as varchar(25)) AS Base FROM cte
WHERE rn=1
UNION ALL
SELECT cte.id,cte.Code,cte.Yr,cte.Rate,cte.rn,
CAST(recursion.Base as int),
CAST(recursion.Base+cte.Rate as varchar(25))
FROM recursion JOIN cte ON recursion.Code=cte.Code AND recursion.rn+1=cte.rn
)
SELECT id,Code,Yr,Rate,
CAST(Base as varchar(10))+ISNULL(' ('+ CAST(Tmp_base as varchar(10))+'+'+CAST(Rate as varchar(10))+')','') AS Base
FROM recursion
ORDER BY 1
OPTION(MAXRECURSION 0)
2) or we can use a faster query without using recursion. but the result is impossible to generate the strings like '107 (100+7)' (only strings like '107')
SELECT *,
100 +
(SELECT ISNULL(SUM(rate),0) /*we need to calculate only the sum in subquery*/
FROM MyTbl AS a
WHERE
a.Code=b.Code /*the year in subquery equals the year in main query*/
AND a.Yr<b.Yr /*main feature in our subquery*/
) AS base
FROM MyTbl AS b