How can I build a query with this format with a sqlite3 database?
CREATE TABLE sample (integer foo);
INSERT INTO sample VALUES (1);
...
INSERT INTO sample VALUES (10);
Format of the result
1,2,3
4,5,6
7,8,9
10
You'll have to add some criteria to group them:
CREATE TABLE sample (integer foo, char(1) bar);
INSERT INTO sample VALUES
(1, 'a'), (2, 'a'), (3, 'a'), (4, 'b'), (5, 'b'), (6, 'b'), (7, 'c') ...;
SELECT GROUP_CONCAT(foo ORDER BY foo, ',')
FROM sample
GROUP BY bar
Edit:
Try this:
select group_concat(foo) from (
select s1.foo, (count(*) - 1) / 3 grp from sample s1
join sample s2 on s1.rowid >= s2.rowid
group by s1.rowid
) final
group by grp
This might not be the best solution (and has some edge cases---if you have a 3 value that is not null), and can probably be put into one query, but I needed the RowId to join on. It should do the trick, though:
CREATE TEMP TABLE split1 (foo1 int);
CREATE TEMP TABLE split2 (foo2 int);
CREATE TEMP TABLE split3 (foo3 int);
INSERT INTO split1
SELECT foo FROM sample WHERE foo % 3 = 1 ORDER BY foo
INSERT INTO split2
SELECT foo FROM sample WHERE foo % 3 = 2 ORDER BY foo
INSERT INTO split3
SELECT foo FROM sample WHERE foo % 3 = 0 ORDER BY foo
SELECT
CASE
WHEN foo2 IS NULL THEN foo1
WHEN foo3 IS NULL THEN foo1||','||foo2
ELSE foo1||','||foo2||','||foo3
END
FROM split1
LEFT JOIN split2
ON split1.RowId = split2.RowId
LEFT JOIN split3
ON split2.RowId = split3.RowId
Related
declare #Character table (id int, [name] varchar(12));
insert into #Character (id, [name])
values
(1, 'tom'),
(2, 'jerry'),
(3, 'dog');
declare #NameToCharacter table (id int, nameId int, characterId int);
insert into #NameToCharacter (id, nameId, characterId)
values
(1, 1, 1),
(2, 1, 3),
(3, 1, 2),
(4, 2, 1);
The Name Table has more than just 1,2,3 and the list to parse on is dynamic
NameTable
id | name
----------
1 foo
2 bar
3 steak
CharacterTable
id | name
---------
1 tom
2 jerry
3 dog
NameToCharacterTable
id | nameId | characterId
1 1 1
2 1 3
3 1 2
4 2 1
I am looking for a query that will return a character that has two names. For example
With the above data only "tom" will be returned.
SELECT *
FROM nameToCharacterTable
WHERE nameId in (1,2)
The in clause will return every row that has a 1 or a 3. I want to only return the rows that have both a 1 and a 3.
I am stumped I have tried everything I know and do not want to resort to dynamic SQL. Any help would be great
The 1,3 in this example will be a dynamic list of integers. for example it could be 1,3,4,5,.....
Filter out a count of how many times the Character appears in the CharacterToName table matching the list you are providing (which I have assumed you can convert into a table variable or temp table) e.g.
declare #Character table (id int, [name] varchar(12));
insert into #Character (id, [name])
values
(1, 'tom'),
(2, 'jerry'),
(3, 'dog');
declare #NameToCharacter table (id int, nameId int, characterId int);
insert into #NameToCharacter (id, nameId, characterId)
values
(1, 1, 1),
(2, 1, 3),
(3, 1, 2),
(4, 2, 1);
declare #RequiredNames table (nameId int);
insert into #RequiredNames (nameId)
values
(1),
(2);
select *
from #Character C
where (
select count(*)
from #NameToCharacter NC
where NC.characterId = c.id
and NC.nameId in (select nameId from #RequiredNames)
) = 2;
Returns:
id
name
1
tom
Note: Providing DDL+DML as shown here makes it much easier for people to assist you.
This is classic Relational Division With Remainder.
There are a number of different solutions. #DaleK has given you an excellent one: inner-join everything, then check that each set has the right amount. This is normally the fastest solution.
If you want to ensure it works with a dynamic amount of rows, just change the last line to
) = (SELECT COUNT(*) FROM #RequiredNames);
Two other common solutions exist.
Left-join and check that all rows were joined
SELECT *
FROM #Character c
WHERE EXISTS (SELECT 1
FROM #RequiredNames rn
LEFT JOIN #NameToCharacter nc ON nc.nameId = rn.nameId AND nc.characterId = c.id
HAVING COUNT(*) = COUNT(nc.nameId) -- all rows are joined
);
Double anti-join, in other words: there are no "required" that are "not in the set"
SELECT *
FROM #Character c
WHERE NOT EXISTS (SELECT 1
FROM #RequiredNames rn
WHERE NOT EXISTS (SELECT 1
FROM #NameToCharacter nc
WHERE nc.nameId = rn.nameId AND nc.characterId = c.id
)
);
A variation on the one from the other answer uses a windowed aggregate instead of a subquery. I don't think this is performant, but it may have uses in certain cases.
SELECT *
FROM #Character c
WHERE EXISTS (SELECT 1
FROM (
SELECT *, COUNT(*) OVER () AS cnt
FROM #RequiredNames
) rn
JOIN #NameToCharacter nc ON nc.nameId = rn.nameId AND nc.characterId = c.id
HAVING COUNT(*) = MIN(rn.cnt)
);
db<>fiddle
DELETE a
FROM TableA a
JOIN TableB b ON a.Field1 = b.Field1 AND a.Field2 = b.Field2;
vs.
DELETE
FROM TableA
WHERE Field1 IN (
SELECT Field1
FROM TableB
) AND Field2 IN (
SELECT Field2
FROM TableB
);
The logical conditions of the two statements are different.
The first statement will delete any row in TableA if both it's Field1 and Field2 correspond to the equivalent columns of a row in TableB.
The second statement will delete any row in TableA if the value of Field1 exists in Field1 of TableB, and the value of Field2 exists in Field2 of TableB - but that doesn't have to be in the same row.
It's easy to see the difference if you change the delete to select.
Here's an example. First, create and populate sample tables (Please save us this step in your future questions):
CREATE TABLE A
(
AInt int,
AChar char(1)
);
CREATE TABLE B
(
BInt int,
BChar char(1)
);
INSERT INTO A (AInt, AChar) VALUES
(1, 'a'), (2, 'a'), (3, 'a'),
(1, 'b'), (2, 'b'), (3, 'b');
INSERT INTO B (BInt, BChar) VALUES
(1, 'a'),
(2, 'b'),
(3, 'c');
The statements (translated to select statements):
SELECT A.*
FROM A
JOIN B
ON AInt = BInt AND AChar = BChar;
SELECT *
FROM A
WHERE AInt IN (
SELECT BInt
FROM B
) AND AChar IN (
SELECT BChar
FROM B
);
Results:
AInt AChar
1 a
2 b
AInt AChar
1 a
2 a
3 a
1 b
2 b
3 b
And you can see a live demo on DB<>Fiddle
I am trying to get output from a table sorted in a predefined sequence of 5 alphabet.
i.e. L > C > E > O > A
by using order by I cant get the desired result. I am using SQL server db.
Can any one please suggest me if I can define a sequence inside a query ?
SO that I get my result in L > C > E > O > A.
Thanks in Advance.
select * from your_table
order by case when some_column = 'L' then 1
when some_column = 'C' then 2
when some_column = 'E' then 3
when some_column = 'O' then 4
when some_column = 'A' then 5
end desc
If you want to use those sorting criteria for two or more queries then you can create a table for this:
CREATE TABLE dbo.CustomSort (
Value VARCHAR(10) PRIMARY KEY,
SortOrder INT NOT NULL
);
GO
INSERT INTO dbo.CustomSort (Value, SortOrder) VALUES ('L', 1);
INSERT INTO dbo.CustomSort (Value, SortOrder) VALUES ('C', 2);
INSERT INTO dbo.CustomSort (Value, SortOrder) VALUES ('E', 3);
INSERT INTO dbo.CustomSort (Value, SortOrder) VALUES ('O', 4);
INSERT INTO dbo.CustomSort (Value, SortOrder) VALUES ('A', 5);
GO
and then you can join the source table (x in this example) with dbo.CustomSort table thus:
SELECT x.Col1
FROM
(
SELECT 'E' UNION ALL
SELECT 'C' UNION ALL
SELECT 'O'
) x(Col1) INNER JOIN dbo.CustomSort cs ON x.Col1 = cs.Value
ORDER BY cs.SortOrder
/*
Col1
----
C
E
O
*/
I you update the dbo.CustomSort table then all queries will use the new sorting criteria.
Say I have a table that looks something like this
ATT A | ATT B
-------------
A | B
D | C
E | F
H | G
and instead I want a table that looks like:
ATT A | ATT B
-------------
A | B
C | D
E | F
G | H
How would I go about doing that? I'm using SQLite.
SQL Server has a case .. end expression that you can use inline in the SQL statement. I think SQLite uses the same syntax. This does what you asked for in SQL Server:
create table #temp (AttA char(1), AttB char(1))
insert into #temp valueS ('A', 'B'), ('D', 'C'), ('E', 'F'), ('H', 'G')
select * from #temp
select case when AttA < AttB then AttA else AttB end as AttA,
case when AttB > AttA then AttB else AttA end as AttB
from #temp
drop table #temp
Supposing the columns have the same type and you just have 2 columns to reorder, you can rely on the min/max functions. With sqlite, when provided with multiple parameters, these functions do not aggregate data from multiple rows.
create table mytable( ATTA char, ATTB char );
insert into mytable values ('A', 'B');
insert into mytable values ('D', 'C');
insert into mytable values ('E', 'F');
insert into mytable values ('H', 'G') ;
select min(ATTA,ATTB),max(ATTA,ATTB) from mytable order by 1,2 ;
A|B
C|D
E|F
G|H
The min/max functions reorder the values in the columns. The order by clause reorders the rows. I think it cannot be generalized to more than 2 columns, except by writing a user defined C function to be called from sqlite.
I have 2 tables: sets and groups. Both are joined using a 3rd table set_has_groups.
I would like to get sets that have ALL groups that I specify
One way of doing it would be
SELECT column1, column2 FROM sets WHERE
id IN(SELECT set_id FROM set_has_group WHERE group_id = 1)
AND id IN(SELECT set_id FROM set_has_group WHERE group_id = 2)
AND id IN(SELECT set_id FROM set_has_group WHERE group_id = 3)
obviously this is not the most beautiful solution
I've also tried this:
SELECT column1, column2 FROM sets WHERE
id IN(SELECT set_id FROM set_has_group WHERE group_id IN(1,2,3) GROUP BY group_id
HAVING COUNT(*) = 3
This looks prettier but the problem is that it takes forever to execute.
While the first query runs in like 200ms the 2nd one takes more than 1 minute.
Any idea why that is?
===UPDATE:
I've played with this some more and I modified the 2nd query like this
SELECT columns FROM `set` WHERE id IN(
select set_id FROM
(
SELECT set_id FROM set_has_group
WHERE group_id IN(1,2,3)
GROUP BY set_id HAVING COUNT(*) = 3
) as temp
)
that is really fast
It's the same as the 2nd query before just that I wrap it in another temporary table
Pretty strange
I am suspecting a small mistyping in the second query.
Really, I am not sure. Probably, the second query is executed via full table scan. At the same time the first one "IN" is really transformed into "EXISTS". So, you can try to use "exists". For example:
...
where 3 = (select count(*) from set_has_group
where group_id in (1, 2, 3) and set_id = id
group by set_id)
Assuming SQL Server, here is a working example with a JOIN that should work better than the IN clauses you are using as long as you have your primary and foreign keys set correctly. I have built joined 5 sets to 3 groups, but set 4 and 5 are not a part of group 3 and will not show in the answer. However, this query is not scalable (for ex. find in group 4, 5, 7, 8 and 13 will require code modifications unless you parse input params into a table variable)
set nocount on
declare #sets table
(
Id INT Identity (1, 1),
Column1 VarChar (50),
Column2 VarChar (50)
)
declare #Set_Has_Group table
(
Set_Id Int,
Group_Id Int
)
insert into #sets values (newid(), newid())
insert into #sets values (newid(), newid())
insert into #sets values (newid(), newid())
insert into #sets values (newid(), newid())
insert into #sets values (newid(), newid())
update #sets set column1 = 'Column1 at Row ' + Convert (varchar, id)
update #sets set column2 = 'Column2 at Row ' + Convert (varchar, id)
insert into #Set_Has_Group values (1, 1)
insert into #Set_Has_Group values (1, 2)
insert into #Set_Has_Group values (1, 3)
insert into #Set_Has_Group values (2, 1)
insert into #Set_Has_Group values (2, 2)
insert into #Set_Has_Group values (2, 3)
insert into #Set_Has_Group values (3, 1)
insert into #Set_Has_Group values (3, 2)
insert into #Set_Has_Group values (3, 3)
insert into #Set_Has_Group values (4, 1)
insert into #Set_Has_Group values (4, 2)
insert into #Set_Has_Group values (5, 1)
insert into #Set_Has_Group values (5, 2)
/* your query with IN */
SELECT column1, column2 FROM #sets WHERE
id IN(SELECT set_id FROM #set_has_group WHERE group_id = 1)
AND id IN(SELECT set_id FROM #set_has_group WHERE group_id = 2)
AND id IN(SELECT set_id FROM #set_has_group WHERE group_id = 3)
/* my query with JOIN */
SELECT * -- Column1, Column2
FROM #sets sets
WHERE 3 = (
SELECT Count (1)
FROM #Set_Has_Group Set_Has_Group
WHERE 1=1
AND sets.Id = Set_Has_Group.Set_Id
AND Set_Has_Group.Group_ID IN (1, 2, 3)
Group by Set_Id
)
Here's a solution that uses a non-correlated subquery and no GROUP BY:
SELECT column1, column2
FROM sets
WHERE id IN (
SELECT g1.set_id FROM set_has_group g1
JOIN set_has_group g2 ON (g1.set_id = g3.set_id)
JOIN set_has_group g3 ON (g1.set_id = g3.set_id)
WHERE g1.group_id = 1 AND g2.group_id = 2 AND g3.group_id = 3);