I am trying to update Data1's ID to Record2's ID when:
Record1's and Record2's Name are the same, and
Weight is greater in Record2.
Record1
| ID | Weight | Name |
|----|--------|------|
| 1 | 10 | a |
| 2 | 10 | b |
| 3 | 10 | c |
Record2
| ID | Weight | Name |
|----|--------|------|
| 4 | 20 | a |
| 5 | 20 | b |
| 6 | 20 | c |
Data1
| ID | Weight |
|----|--------|
| 4 | 40 |
| 5 | 40 |
I have tried the following SQLite query:
update data1
set id =
(select record2.id
from record2,record1
where record1.name=record2.name
and record1.weight<record2.weight)
where id in
(select record1.id
from record1, record2
where record1.name=record2.name
and record1.weight<record2.weight)
Using the above query Data1's id is updated to 4 for all records.
NOTE: Record1's ID is the foreign key for Data1.
For the given data set the following seems to serve the cause:
update data1
set id =
(select record2.id
from record2,record1
where
data1.id = record1.id
and record1.name=record2.name
and record1.weight<record2.weight)
where id in
(select record1.id
from record1, record2
where
record1.id in (select id from data1)
and record1.name=record2.name
and record1.weight<record2.weight)
;
See it in action: SQL Fiddle.
Please comment if and as this requires adjustment / further detail.
Related
I have a database that I don't control the source of directly and results in errant '0' entries which mess up generated graphs with these drops to zero. I am able to manipulate the data after the fact and update that database.
It is acceptable that the last known good value can be used instead and so I am trying to make a general query that will remove all the zeros and populate it with the last known value.
Luckily, every entry includes the ID of the last entry and so it is a matter of simply looking back and grabbing it.
I have got very close to a final answer, but instead of updating with the last good value, it just uses the first value over and over again.
dummy data
CREATE TABLE tbl(id INT,r INT,oid INT);
INSERT INTO tbl VALUES(1,10,0);
INSERT INTO tbl VALUES(2,20,1);
INSERT INTO tbl VALUES(3,0,2);
INSERT INTO tbl VALUES(4,40,3);
INSERT INTO tbl VALUES(5,50,4);
INSERT INTO tbl VALUES(6,0,5);
INSERT INTO tbl VALUES(7,70,6);
INSERT INTO tbl VALUES(8,80,7);
SELECT * FROM tbl;
OUTPUT:
| id| r |oid|
|---|----|---|
| 1 | 10 | 0 |
| 2 | 20 | 1 |
| 3 | 0 | 2 | ** NEEDS FIXING
| 4 | 40 | 3 |
| 5 | 50 | 4 |
| 6 | 0 | 5 | ** NEEDS UPDATE
| 7 | 70 | 6 |
| 8 | 80 | 7 |
I have worked several queries to get results around what I am after:
All zero entries:
SELECT * FROM tbl WHERE r = 0;
OUTPUT:
| id | r | oid |
|----|----|-----|
| 3 | 0 | 2 |
| 6 | 0 | 5 |
Output only the those rows with the preceding good row
SELECT * FROM tbl WHERE A in (
SELECT id FROM tbl WHERE r = 0
UNION
SELECT oid FROM tbl WHERE r = 0
)
OUTPUT:
| id| r |oid|
|---|----|---|
| 2 | 20 | 1 |
| 3 | 0 | 2 |
| 5 | 50 | 4 |
| 6 | 0 | 5 |
Almost works
This is as close as I have got, it does change all the zero's, but it changes them all to the value of the first lookup
UPDATE tbl
SET r = (SELECT r
FROM tbl
WHERE id in (SELECT oid
FROM tbl
WHERE r = 0)
) WHERE r = 0 ;
OUTPUT:
| id| r |oid|
|---|----|---|
| 1 | 10 | 0 |
| 2 | 20 | 1 |
| 3 | 20 | 2 | ** GOOD
| 4 | 40 | 3 |
| 5 | 50 | 4 |
| 6 | 20 | 5 | ** BAD, should be 50
| 7 | 70 | 6 |
| 8 | 80 | 7 |
If it helps, I created this fiddle here that I've been playing with:
http://sqlfiddle.com/#!5/8afff/1
For this sample data all you have to do is use the correct correlated subquery that returns the value of r from the row with id equal to the current oid in the WHERE clause:
UPDATE tbl AS t
SET r = (SELECT tt.r FROM tbl tt WHERE tt.id = t.oid)
WHERE t.r = 0;
See the demo.
I'm trying to compose an SQLite query and I've found a problem that's beyond my skillset. I'm trying to output columns that are based on the rows of another referenced table.
Food_List:
| food_id | name |
|---------|-----------|
| 1 | Apple |
| 2 | Orange |
| 3 | Pear |
Nutrient_Definition:
| nutrient_id | name |
|-------------|-----------|
| 21 | Carbs |
| 22 | Protein |
| 23 | Fat |
Nutrient_Data:
| food_id | nutrient_id | value |
|---------|-------------|-------|
| 1 | 21 | 50 |
| 1 | 22 | 24 |
| 1 | 23 | 63 |
| 2 | 22 | 12 |
| 2 | 23 | 95 |
| 3 | 21 | 66 |
| 3 | 22 | 87 |
| 3 | 23 | 38 |
Output:
| food_id | name | Carbs | Protein | Fat |
|---------|-----------|-------|---------|-----|
| 1 | Apple | 50 | 24 | 63 |
| 2 | Orange | | 12 | 95 |
| 3 | Pear | 66 | 87 | 38 |
(Note that Orange does not have a "Carbs" entry in the Nutrient_Data table)
I believe the following will do what you want :-
DROP TABLE IF EXISTS food_list;
CREATE TABLE IF NOT EXISTS food_list(food_id INTEGER PRIMARY KEY, name TEXT);
DROP TABLE IF EXISTS nutrient_definition;
CREATE TABLE IF NOT EXISTS nutrient_definition(nutrient_id INTEGER PRIMARY KEY, name TEXT);
DROP TABLE IF EXISTS nutrient_data;
CREATE TABLE IF NOT EXISTS nutrient_data(food_id INTEGER, nutrient_id INTEGER, value INTEGER);
INSERT INTO food_list (name) VALUES
('apple'),('orange'),('pear')
;
INSERT INTO nutrient_definition (name) VALUES
('carbs'),('protien'),('fat')
;
INSERT INTO nutrient_data VALUES
(1,1,50),(1,2,24),(1,3,63),
(2,2,12),(2,3,95),
(3,1,66),(3,2,87),(3,3,38)
;
SELECT food_list.food_id,food_list.name,
(
SELECT value
FROM nutrient_data
WHERE nutrient_data.food_id = food_list.food_id AND
nutrient_data.nutrient_id = (SELECT nutrient_definition.nutrient_id FROM nutrient_definition WHERE nutrient_definition.name = 'carbs')
),
(
SELECT value
FROM nutrient_data
WHERE nutrient_data.food_id = food_list.food_id AND
nutrient_data.nutrient_id = (SELECT nutrient_definition.nutrient_id FROM nutrient_definition WHERE nutrient_definition.name = 'protien')
),
(
SELECT value
FROM nutrient_data
WHERE nutrient_data.food_id = food_list.food_id AND
nutrient_data.nutrient_id = (SELECT nutrient_definition.nutrient_id FROM nutrient_definition WHERE nutrient_definition.name = 'fat')
)
FROM food_list
;
Results in :-
I'm working with SQL Server and I have this 3 tables
STUDENTS
| id | student |
-------------
| 1 | Ronald |
| 2 | Jenny |
SCORES
| id | score | period | student |
| 1 | 8 | 1 | 1 |
| 2 | 9 | 2 | 1 |
PERIODS
| id | period |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
And I want a query that returns this result:
| student | score1 | score2 | score3 | score4 |
| Ronald | 8 | 9 | null | null |
| Jenny | null | null | null | null |
As you can see, the number of scores depends of the periods because sometimes it can be 4 o 3 periods.
I don't know if I have the wrong idea or should I make this in the application, but I want some help.
You need to PIVOT your data e.g.
select Y.Student, [1], [2], [3], [4]
from (
select T.Student, P.[Period], S.Score
from Students T
cross join [Periods] P
left join Scores S on S.[Period] = P.id and S.Student = T.id
) X
pivot
(
sum(Score)
for [Period] in ([1],[2],[3],[4])
) Y
Reference: https://learn.microsoft.com/en-us/sql/t-sql/queries/from-using-pivot-and-unpivot?view=sql-server-20
Assume I have two tables, e.g.:
table_1:
+----+-------+------------+--
| id | name | table_2_id | ...
+----+-------+------------+--
| 1 | test1 | 2 | ...
| 2 | test2 | 1 | ...
| 3 | test3 | 1 | ...
...
and
table_2:
+----+------+--
| id | name | ...
+----+------+--
| 1 | xxx | ...
| 2 | yyy | ...
| 3 | zzz | ...
...
Now I want to select everything from table_2 and add another column containing in every cell a collection of all names from table_1 where table_2_id corresponds with the current id from table_2:
output:
+----+------+-----+--------------+
| id | name | ... | link |
+----+------+-----+--------------+
| 1 | xxx | ... | test2, test3 |
| 2 | yyy | ... | test1 |
| 3 | zzz | ... | % |
...
How can I achieve this?
This can be done with a correlated subquery.
To combine values from multiple rows, use group_concat:
SELECT id,
name,
(SELECT group_concat(name)
FROM table_1
WHERE table_2_id = table_2.id
) AS link
FROM table_2;
I have the following table in an sqlite database
+----+-------------+-------+
| ID | Week Number | Count |
+----+-------------+-------+
| 1 | 1 | 31 |
| 2 | 2 | 16 |
| 3 | 3 | 73 |
| 4 | 4 | 59 |
| 5 | 5 | 44 |
| 6 | 6 | 73 |
+----+-------------+-------+
I want to get the following table out. Where I get this weeks sales as one column and then the next column will be last weeks sales.
+-------------+-----------+-----------+
| Week Number | This_Week | Last_Week |
+-------------+-----------+-----------+
| 1 | 31 | null |
| 2 | 16 | 31 |
| 3 | 73 | 16 |
| 4 | 59 | 73 |
| 5 | 44 | 59 |
| 6 | 73 | 44 |
+-------------+-----------+-----------+
This is the select statement i was going to use:
select
id, week_number, count,
(select count from tempTable
where week_number = (week_number-1))
from
tempTable;
You are comparing values in two different rows. When you are just writing week_number, the database does not know which one you mean.
To refer to a column in a specific table, you have to prefix it with the table name: tempTable.week_number.
And if both tables have the same name, you have to rename at least one of them:
SELECT id,
week_number,
count AS This_Week,
(SELECT count
FROM tempTable AS T2
WHERE T2.week_number = tempTable.week_number - 1
) AS Last_Week
FROM tempTable;
In case of you want to take a query upon a same table twice, you have to put aliases on the original one and its replicated one to differentiate them
select a.week_number,a.count this_week,
(select b.count from tempTable b
where b.week_number=(a.week_number-1)) last_week
from tempTable a;