I have the following tables:
book_tbl:
book_instance_id | book_type_id | library_instance_id | location_id | book_index
1 | 70000 | 2 | 0 | 1
2 | 70000 | 2 | 0 | 2
3 | 70000 | 2 | 0 | 3
4 | 70000 | 3 | 0 | 1
5 | 70000 | 3 | 0 | 2
6 | 70000 | 3 | 0 | 3
7 | 70000 | 4 | 1 | 1
8 | 70000 | 4 | 1 | 2
9 | 70000 | 4 | 1 | 3
and library_tbl:
library_instance_id | library_type_id | location_id
2 | 1000 | 0
3 | 1001 | 0
4 | 1000 | 1
I would like to update the field book_type_id in book_tbl only for the first element (index) in library_type_id 1000
To retrieve this information I used sqlite query:
SELECT * FROM ( ( SELECT *
FROM library_tbl
WHERE library_type_id=1000 ) t1
join book_tbl t2 on t1.location_id=t2.location_id
AND t1.library_instance_id=t2.library_instance_id
AND book_index=1 )
How could I use the query above with UPDATE query to update rows 1 and 7:
UPDATE book_tbl SET book_type_id=15000 WHERE ????
Use EXISTS with a correlated subquery to check whether the corresponding library row exists:
UPDATE book_tbl
SET book_type_id = 15000
WHERE EXISTS (SELECT 1
FROM library_tbl
WHERE library_type_id = 1000
AND location_id = book_tbl.location_id
AND library_instance_id = book_tbl.library_instance_id)
AND book_index = 1;
Related
I have two dataframes one with the original information and the second one with corrections about the first observations. I would like to create a function or find a way to replace in multiple columns the information I have in my first dataframe with the new information I received. I have an ID to identify the observations that need to be replace but since so many columns will be changing for certain IDs I don´t know which will be the appropriate way of changing them.
My first data frame has 500 columns and 1000 observations and my second data frame has 100 columns and 800 observations that will change the original dataframe. I don´t know how to efficiently replace those values according to the ID
Here is an example of what the 2 dataframes look like, I need to replace in multiple columns just some values and a merge is not the most efficient options since I have more than 100 columns at least that will need changes in some of the observations.
I just need to replace the new info and keep the old one
enter image description here
Dataframe 1
|ID | X1 | X2 | X3 | X4 | XN |
|a1 | 1 | 1 | 1 | 1 | 1 |
|a2 | 2 | 2 | 2 | 2 | 2 |
|a3 | 3 | 3 | 3 | 3 | 3 |
|a4 | 4 | 4 | 4 | 4 | 4 |
|a5 | 5 | 5 | 5 | 5 | 5 |
|an | 6 | 6 | 6 | 6 | 6 |
dataframe 2
|ID | X1 | X2 | X4|
|a1 | 8 | | 4 |
|a3 | | | 2 |
|a4 | 2 | 9 | |
|an | 1 | | 3 |
The outcome should have the old values of dataframe 1 just with the replacements I got from dataframe 2
outcome
|ID | X1 | X2 | X3 | X4 | XN |
|a1 | 8 | 1 | 1 | 4 | 1 |
|a2 | 2 | 2 | 2 | 2 | 2 |
|a3 | 3 | 3 | 3 | 2 | 3 |
|a4 | 2 | 9 | 4 | 4 | 4 |
|a5 | 5 | 5 | 5 | 5 | 5 |
|an | 1 | 6 | 6 | 3 | 6 |
I want to subtract values in the "place" column for each record returned in a "race", "bib", "split" group by so that a "diff" column appears like so.
Desired Output:
race | bib | split | place | diff
----------------------------------
10 | 514 | 1 | 5 | 0
10 | 514 | 2 | 3 | 2
10 | 514 | 3 | 2 | 1
10 | 17 | 1 | 8 | 0
10 | 17 | 2 | 12 | -4
10 | 17 | 3 | 15 | -3
I'm new to using the coalesce statement and the closest I have come to the desired output is the following
select a.race,a.bib,a.split, a.place,
coalesce(a.place -
(select b.place from ranking b where b.split < a.split), a.place) as diff
from ranking a
group by race,bib, split
which produces:
race | bib | split | place | diff
----------------------------------
10 | 514 | 1 | 5 | 5
10 | 514 | 2 | 3 | 2
10 | 514 | 3 | 2 | 1
10 | 17 | 1 | 8 | 8
10 | 17 | 2 | 12 | 11
10 | 17 | 3 | 15 | 14
Thanks for looking!
To compute the difference, you have to look up the value in the row that has the same race and bib values, and the next-smaller split value:
SELECT race, bib, split, place,
coalesce((SELECT r2.place
FROM ranking AS r2
WHERE r2.race = ranking.race
AND r2.bib = ranling.bib
AND r2.split < ranking.split
ORDER BY r2.split DESC
LIMIT 1
) - place,
0) AS diff
FROM ranking;
The following query works in SQL Server but not in SQLite 3.8.7 and I would like to know why.
Table
l | r
0 | 10
0 | 2
8 | 10
Query
SELECT * FROM Segments AS s1
LEFT JOIN Segments AS s2
ON ((s2.l <= s1.l AND s2.r > s1.r)
OR (s2.l < s1.l AND s2.r >= s1.r));
Expected output
s1.l | s1.r | s2.l | s2.r
0 | 10 | null | null
0 | 2 | 0 | 10
8 | 10 | 0 | 10
However I got
s1.l | s1.r | s2.l | s2.r
0 | 10 | 0 | 2
0 | 2 | 0 | 10
8 | 10 | 0 | 10
And when I switched the expression order i.e
((s2.l < s1.l AND s2.r >= s1.r) (s2.l <= s1.l AND s2.r > s1.r))
I got
s1.l | s1.r | s2.l | s2.r
0 | 10 | 8 | 10
0 | 2 | 0 | 10
8 | 10 | 0 | 10
This was solved by using | instead of OR, but I am wondering why OR did not work?
Heres the example on SQLFiddle
http://sqlfiddle.com/#!7/15859/22/1
Thanks
This is a bug that was fixed in SQLite 3.8.7.2.
I have a probably pretty hard question/situation:
I have a database to divide several tasks to some workers.
In the next example I have two tasks (Task 1 and Task 2) and 4 Employee's(1, 2, 3 and 4)
The maximum employee's that works on 1 task is three. Therefore I have 3 columns to get all possible options (in this example, not every option is shown!). The last column is a value which indicate how good the option is (the higher the number, the better).
The goal is to get the most optimal situation which means:
Every employee have to do one task (and cannot do 2 tasks)
The sum of the values is the highest possible value
+------------+------------+------------+------+--------+
| Employee_1 | Employee_2 | Employee_3 | Task | Value |
+------------+------------+------------+------+--------+
| 1 | | | 1 | 5.0 |
| 2 | | | 1 | -2.5 |
| 3 | | | 1 | 1.0 |
| 4 | | | 1 | 0.5 |
| 1 | 2 | | 1 | 0.5 |
| 1 | 4 | | 1 | 5,0 |
| 1 | 2 | 3 | 1 | 0.33 |
| 2 | 3 | | 1 | -4.5 |
| 2 | 3 | 4 | 1 | -6.5 |
| 3 | 4 | | 1 | 3.0 |
| 1 | | | 2 | 1.0 |
| 2 | | | 2 | 2.0 |
| 3 | | | 2 | -5.0 |
| 4 | | | 2 | 3.0 |
| 1 | 2 | | 2 | -2.0 |
| 1 | 2 | 3 | 2 | -3.5 |
| 2 | 3 | | 2 | 5.0 |
| 2 | 3 | 4 | 2 | 0.5 |
| 3 | 4 | | 2 | 2.0 |
+------------+------------+------------+------+--------+
As you can see: sometimes it is better for the productivity:
Employee 1 gets a value of 5 on task 1
Employee 4 gets a value of 0.5 on task 1
Employee 1 and 3 gets a value of 5,0 on task 1
In this situation it is better that Employee 1 and 3 works separate and the query should give both lines:
+------------+-------------+------------+-------+---------+
| Employee_1 | Employee_2 | Employee_3 | Task | Value |
+------------+-------------+------------+-------+---------+
| 1 | | | 1 | 5.0 |
| 4 | | | 1 | 0.5 |
+------------+-------------+------------+-------+---------+
The real solution for this example should be:
+------------+-------------+------------+-------+---------+
| Employee_1 | Employee_2 | Employee_3 | Task | Value |
+------------+-------------+------------+-------+---------+
| 1 | | | 1 | 5.0 |
| 2 | 3 | | 2 | 5.0 |
| 4 | | | 2 | 3.0 |
+------------+-------------+------------+-------+---------+
Since employee 1 has a very high value on its own on task 1
Employee 3 is really bad on his own, but together with employee 2 they do great on task 2
Employee 4 is the only one who is left en this employee is pretty good at task 2.
The problem is to write the query to get this result
I have a dataset that looks like
| ID | Category | Failure |
|----+----------+---------|
| 1 | a | 0 |
| 1 | b | 0 |
| 1 | b | 0 |
| 1 | a | 0 |
| 1 | c | 0 |
| 1 | d | 0 |
| 1 | c | 0 |
| 1 | failure | 1 |
| 2 | c | 0 |
| 2 | d | 0 |
| 2 | d | 0 |
| 2 | b | 0 |
This is data where each ID potentially ends in a failure event, through an intermediate sequence of events {a, b, c, d}. I want to be able to count the number of IDs for which each of those intermediate events occur by failure event.
So, I would like a table of the form
| | a | b | c | d |
|------------+---+---+---+---|
| Failure | 4 | 5 | 6 | 2 |
| No failure | 9 | 8 | 6 | 9 |
where, for example, the number 4 indicates that in 4 of the IDs where a occurred ended in failure.
How would I go about doing this in R?
You can use table for example:
dat <- data.frame(categ=sample(letters[1:4],20,rep=T),
failure=sample(c(0,1),20,rep=T))
res <- table(dat$failure,dat$categ)
rownames(res) <- c('Failure','No failure')
res
a b c d
Failure 3 2 2 1
No failure 1 2 4 5
you can plot it using barplot:
barplot(res)
EDIT to get this by ID, you can use by for example:
dat <- data.frame(ID=c(rep(1,9),rep(2,11)),categ=sample(letters[1:4],20,rep=T),
failure=sample(c(0,1),20,rep=T))
by(dat,dat$ID,function(x)table(x$failure,x$categ))
dat$ID: 1
a b c d
0 1 2 1 3
1 1 1 0 0
---------------------------------------------------------------------------------------
dat$ID: 2
a b c d
0 1 2 3 0
1 1 3 1 0
EDIT using tapply
Another way to get this is using tapply
with(dat,tapply(categ,list(failure,categ,ID),length))