I would like to know whether it is possible to use a SELECT statement in SQLite to merge the data from two rows into one, similar to how is suggested in the SQL Server forum below.
Consider the scenario below which is based on SQL Server (taken from http://forums.aspfree.com/microsoft-sql-server-14/merge-the-two-rows-in-one-row-245550.html)
Given there is a table
Emp
ID | Name |
1 | x |
1 | P |
2 | y |
2 | Q |
3 | W |
We want the resulting data from the select statement to output:
Emp_Data
Id | Name-1 | Name-2 |
1 | x | P |
2 | y | Q |
3 | w | |
The answer in the post suggests the following SQL as a possible solution:
SELECT
a.ID,
[Name-1] = ISNULL((
SELECT TOP 1 Name
FROM emp
WHERE ID = a.ID),''),
[Name-2] = ISNULL((
SELECT TOP 1 b.Name
FROM emp b
WHERE b.ID = a.ID
AND Name NOT IN(
SELECT TOP 1 Name
FROM emp
WHERE ID = b.ID
)),'')
FROM emp a
GROUP BY a.ID
Using SQLite is it possible to generate the columns [Name-1] & [Name-2] using nested SELECT statements like we can do above in SQL Server?
SELECT
a.ID,
COALESCE(a.Name,'') as "Name-1",
COALESCE((SELECT b.Name FROM Emp b
WHERE b.ID = a.ID
AND b.rowid != a.rowid LIMIT 1),'') as "Name-2"
FROM emp a
GROUP BY a.ID
Doug's solution didn't work for me. The code below, however, did work for me but it's very slow...
SELECT
a.ID,
a.Name AS Name1,
(SELECT b.Name FROM Emp b
WHERE b.ID = a.ID
AND b.Name != a.Name LIMIT 1) AS Name2
FROM emp a
GROUP BY a.ID
try this:::
select id, group_concat(name) from emp group by id;
;)
Related
I'm having probleme with a SQL request.
I have two tables:
main table is
Id | Name
1 | Name_1
2 | Name_2
keyword table
Id | _mainId | key
1 | 1 | kw1
2 | 1 | kw2
3 | 1 | kw3
4 | 2 | kw2
5 | 2 | kw4
I would like a request which return the Id and Name of the mane table with all the keywords selected
something like this :
SELECT DISTINCT(t1.Id), t1.Name
FROM main t1
INNER JOIN keywords t2 ON t2._Main = t1.Id
WHERE t2.keyword = 'kw2' AND t2.keyword = 'kw4';
In the query below, the subquery aliased as t2 identifies all IDs having both the keywords 'kw2' and 'kw4'. I then join the main table to this subquery to bring in the name information for those matching IDs.
SELECT t1.Id, t1.Name
FROM main t1
INNER JOIN
(
SELECT _mainId
FROM keywords
WHERE keyword IN ('kw2', 'kw4')
GROUP BY _mainId
HAVING COUNT(DISTINCT keyword) = 2
) t2
ON t1.Id = t2._mainId
Try this:
SELECT DISTINCT
t1.Id, t1.Name
FROM
main t1
INNER JOIN keywords t2 ON t2._mainId=t1.Id
WHERE
t2.key IN ('kw2', 'kw4');
When I search for how to compare two tables in SQLite, and see what's differ, I mostly find answers like this:
SELECT B.id FROM B LEFT JOIN A ON B.id = A.id WHERE A.id IS NULL
and yes, it's correct if you want do find all the elements (or values for keys named 'id' in this case) in table B that is not in table A, i.e. all the new elements in B if B is a later version of A.
But what if I want to find all the id:s in B where the value for a certain key (or keys) deviate from the corresponding value in A? For example, if I have two tables, A and B with id:s and positions, and I want to get the result id=3 in this case, because it is the element in B that has a value that differ. What would be the easiest way to do that?
Table A Table B
id | x_value | y_value id | x_value | y_value
----------------------- -----------------------
1 | 29.9563 | 12.6764 1 | 29.9563 | 12.6764
2 | 45.5843 | 7.6733 2 | 45.5843 | 7.6733
3 | 28.2313 | 15.6579 3 | 39.2003 | 15.6579
Result:
id
--
3
You can do it with a inner join with your condition in the where clause.
select a.id
from tableA a join tableB b on a.id = b.id
where ifnull(a.x_value, 0) <> ifnull(b.x_value, 0)
or ifnull(a.y_value, 0) <> ifnull(b.y_value, 0)
You can use INTERSECT:
LiveDemo
SqlFiddleDemo
SELECT tA.id
FROM TableA tA
JOIN TableB tB
ON tA.id = tB.id
WHERE NOT EXISTS( SELECT tA.x_value, tA.y_value
INTERSECT
SELECT tB.x_value, tB.y_value);
I like this solution, because it is easy to extend. Just add new column names. No need to handle NULL manually.
I agree with shawnt00 that you can read the question that the goal was to find all the id:s where values have changed between the two tables AND id:s of new instances inserted to the second table. Here is the select-statement to accomplish that, if anyone is interested:
select b.id
from b left join a on b.id = a.id
where ifnull(a.x_value, 0) <> ifnull(b.x_value, 0)
or ifnull(a.y_value, 0) <> ifnull(b.y_value, 0)
or a.id is null;
I have 2 tables:
tblTransactions:
transID | type | userID
tblusers:
userID | name ;
Now I want my results to be like:
name |count( transactionType1(where type=1)) | transactionType1(where type=2)
mr.1 | 2 | 4
mr.2 | 3 | 5
Thanks for your help
Group by the user and then you can use aggregate functions like sum to count the type (with a condition)
select u.name,
sum(type = 1) as type1_count,
sum(type = 2) as type2_count
from tblusers u
left join tblTransactions t on u.userid = t.userid
group by u.name
I have one table in which I have name of all the tables.
Table
ID | Name | table_name|
1 | A | abc
2 | B | xyz
3 | C | 123
Now I have tables abc, xyz and 123 on the basis of name I want to get the table name and then from that table I want it complete data
SELECT *
FROM (SELECT table_name FROM Table 1 WHERE Table1.Name = 'A')
This query is not working in PostgreSQL
Please try after modifying the query as follows:
SELECT *
FROM (SELECT table_name FROM Table 1 WHERE Table1.Name = 'A') As TblName
I have 4 columns in a table called musics - 'artist','genre', 'writer' , 'producer'.
I need to write a query such that, it returns a value 0 , if there are no repetition of values corresponding to the column name; if there is a repetition of values, it should return a value 1, corresponding to that column name.
Any help is much appreciated
SELECT (COUNT(artist) <> COUNT(DISTINCT artist)) artist,
(COUNT(genre) <> COUNT(DISTINCT genre)) genre,
(COUNT(writer) <> COUNT(DISTINCT writer)) writer,
(COUNT(producer) <> COUNT(DISTINCT producer)) producer
FROM musics
Another version
SELECT
( SELECT (COUNT(*) > 0)
FROM (SELECT 1 FROM musics GROUP BY artist HAVING COUNT(*) > 1) a
) artist,
( SELECT (COUNT(*) > 0)
FROM (SELECT 1 FROM musics GROUP BY genre HAVING COUNT(*) > 1) g
) genre,
( SELECT (COUNT(*) > 0)
FROM (SELECT 1 FROM musics GROUP BY writer HAVING COUNT(*) > 1) w
) writer,
( SELECT (COUNT(*) > 0)
FROM (SELECT 1 FROM musics GROUP BY producer HAVING COUNT(*) > 1) p
) producer
Sample data
| artist | genre | writer | producer |
------------------------------------------
| artist1 | genre1 | writer1 | producer1 |
| artist2 | genre2 | writer1 | producer2 |
| artist1 | genre3 | writer3 | producer3 |
Sample output:
| artist | genre | writer | producer |
--------------------------------------
| 1 | 0 | 1 | 0 |
SQLFiddle
For Artist
select convert(bit,(count(1)-1))
from table_name
group by artist -- <-- Replace artist with column name for which duplicate
write a select count statement using distinct with specified column and another select count without distinct and compare both of them based on your requirement
you can use 4 different query with union & each query must contain count(column name) + group by clause