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Pivoting in DB2
(3 answers)
Closed 5 years ago.
I have table A, below, where for each unique id, there are three codes with some value.
ID Code Value
---------------------
11 1 x
11 2 y
11 3 z
12 1 p
12 2 q
12 3 r
13 1 l
13 2 m
13 3 n
I have a second table B with format as below:
Id Code1_Val Code2_Val Code3_Val
Here there is just one row for each unique id. I want to populate this second table B from first table A for each id from the first table.
For the first table A above, the second table B should come out as:
Id Code1_Val Code2_Val Code3_Val
---------------------------------------------
11 x y z
12 p q r
13 l m n
How can I achieve this in a single SQL query?
select Id,
max(case when Code = '1' then Value end) as Code1_Val,
max(case when Code = '2' then Value end) as Code2_Val,
max(case when Code = '3' then Value end) as Code3_Val
from TABLEA
group by Id
SELECT Id,
max(DECODE(Code, 1, Value)) AS Code1_Val,
max(DECODE(Code, 2, Value)) AS Code2_Val,
max(DECODE(Code, 3, Value)) AS Code3_Val
FROM A
group by Id
If your version doesn't have DECODE(), you can also use this:
INSERT INTO B (id, code1_val, code2_val, code3_val)
WITH Ids (id) as (SELECT DISTINCT id
FROM A) -- Only to construct list of ids
SELECT Ids.id, a1.value, a2.value, a3.value
FROM Ids -- or substitute the actual id table
JOIN A a1
ON a1.id = ids.id
AND a1.code = 1
JOIN A a2
ON a2.id = ids.id
AND a2.code = 2
JOIN A a3
ON a3.id = ids.id
AND a3.code = 3
(Works on my V6R1 DB2 instance, and have an SQL Fiddle Example).
Here is a SQLFiddle example
insert into B (ID,Code1_Val,Code2_Val,Code3_Val)
select Id, max(V1),max(V2),max(V3) from
(
select ID,Value V1,'' V2,'' V3 from A where Code=1
union all
select ID,'' V1, Value V2,'' V3 from A where Code=2
union all
select ID,'' V1, '' V2,Value V3 from A where Code=3
) AG
group by ID
Here is the SQL Query:
insert into pivot_insert_table(id,code1_val,code2_val, code3_val)
select * from (select id,code,value from pivot_table)
pivot(max(value) for code in (1,2,3)) order by id ;
WITH Ids (id) as
(
SELECT DISTINCT id FROM A
)
SELECT Ids.id,
(select sub.value from A sub where Ids.id=sub.id and sub.code=1 fetch first rows only) Code1_Val,
(select sub.value from A sub where Ids.id=sub.id and sub.code=2 fetch first rows only) Code2_Val,
(select sub.value from A sub where Ids.id=sub.id and sub.code=3 fetch first rows only) Code3_Val
FROM Ids
You want to pivot your data. Since DB2 has no pivot function, yo can use Decode (basically a case statement.)
The syntax should be:
SELECT Id,
DECODE(Code, 1, Value) AS Code1_Val,
DECODE(Code, 2, Value) AS Code2_Val,
DECODE(Code, 3, Value) AS Code3_Val
FROM A
Related
Say I have a BQ table containing the following information
id
test.name
test.score
1
a
5
b
7
2
a
8
c
3
Where test is nested. How would I pivot test into the following table?
id
a
b
c
1
5
7
2
8
3
I cannot pivot test directly, as I get the following error message at pivot(test): Table-valued function not found. Previous questions (1, 2) don't deal with nested columns or are outdated.
The following query looks like a useful first step:
select a.id, t
from `table` as a,
unnest(test) as t
However, this just provides me with:
id
test.name
test.score
1
a
5
1
b
7
2
a
8
2
c
3
Conditional aggregation is a good approach. If your tables are large, you might find that this has the best performance:
select t.id,
(select max(tt.score) from unnest(t.score) tt where tt.name = 'a') as a,
(select max(tt.score) from unnest(t.score) tt where tt.name = 'b') as b,
(select max(tt.score) from unnest(t.score) tt where tt.name = 'c') as c
from `table` t;
The reason I recommend this is because it avoids the outer aggregation. The unnest() happens without shuffling the data around -- and I have found that this is a big win in terms of performance.
One option could be using conditional aggregation
select id,
max(case when test.name='a' then test.score end) as a,
max(case when test.name='b' then test.score end) as b,
max(case when test.name='c' then test.score end) as c
from
(
select a.id, t
from `table` as a,
unnest(test) as t
)A group by id
Below is generic/dynamic way to handle your case
EXECUTE IMMEDIATE (
SELECT """
SELECT id, """ ||
STRING_AGG("""MAX(IF(name = '""" || name || """', score, NULL)) AS """ || name, ', ')
|| """
FROM `project.dataset.table` t, t.test
GROUP BY id
"""
FROM (
SELECT DISTINCT name
FROM `project.dataset.table` t, t.test
ORDER BY name
)
);
If to apply to sample data from your question - output is
Row id a b c
1 1 5 7 null
2 2 8 null 3
I'm not sure if the solution for this question is incredible simple or not possible in pure SQL.
I have a simple table with 2 columns
Number Text
1 a
1 b
2 m
3 x
3 y
3 z
Now the task is:
Search all repeated numbers and show the "Text" which uses these duplicated numbers.
We see: 1 is used twice (with a and b), 3 is used with x and y and z. But no line is completely duplicated.
Edit:
So I expect something like this.
Dup_Num Text
1 a
1 b
3 x
3 y
3 z
The search for the duplicate is easy, but I don't have an idea how to connect is with "Text", because when I add "Text" to my SELECT I have to use it for GROUP and this give no duplicates ..
Thanks for help on a lousy day ..
If I understand correctly, you can use exists:
select t.*
from t
where exists (select 1 from t t2 where t2.number = t.number and t2.text <> t.text)
order by t.number;
For performance, you want an index on (number, text).
The canonical way to find duplicates in SQL is the self join.
In your example:
select s1.*
from stuff s1
inner join stuff s2
on s1.number = s2.number
and s1.text <> s2.text
In your case, you might want to use LISTAGG to group those values and its relation to the other column
SQL> with result
as (
select '1' as c1 , 'a' as c2 from dual union all
select '1' as c1 , 'b' as c2 from dual union all
select '2' as c1 , 'm' as c2 from dual union all
select '3' as c1 , 'x' as c2 from dual union all
select '3' as c1 , 'y' as c2 from dual union all
select '3' as c1 , 'z' as c2 from dual )
select c1, listagg(c2,',') within group(order by c1) as c3 from result
group by c1;
C C3
- --------------------
1 a,b
2 m
3 x,y,z
SQL>
This might also help you.
select * from t where Number in
(select Number from t group by Number having count(*) > 1)
order by Text
Fiddle
I have a table Fields. Example:-
id remote unique_id
1 23 30007
1 24 30008
1 1 30009
2 4 30007
2 5 30008
2 1 30009
3 6 30007
3 7 30008
3 2 30009
here i want to get sum of unique_id field=30008 remote value where unique_id field=30009 remote value = 1;
basically, what i want is:
(query 1)
select SUM(remote) from Fields where unquie_id = '30008';
and one added filter where:(query 2)
select remote from Fields where unquie_id = '30009';
i want to select the _id record of query 2 where remote=1 for my query 1.
So the above output would be: 24+5=29.
Here i am selecting _id as 1,2. _id =3 would be rejected as it remote for unique_id = 30009 is 2.
This might be simple for you guys but i am new with sqlite. Hence please help.
If I understand your question correctly, then you want to sum the remote column where the unique_id is 30008, but only for those id groups having remote=1 and unique_id=30009.
SELECT SUM(f1.remote)
FROM Fields f1
INNER JOIN
(
SELECT id
FROM Fields
GROUP BY id
HAVING SUM(CASE WHEN unique_id = '30009' AND remote = 1 THEN 1 ELSE 0 END) > 0
) f2
ON f1.id = f2.id
WHERE unique_id = '30008';
I didn't actually run it, but something like this should do what you need:
select SUM(remote) from Fields as F where F.unique_id = '30008' and F.id in (select remote from Fields as G where G.unique_id = '30009');
So I tested it:
create table Fields(id integer, remote integer, unique_id integer);
insert into Fields(id, remote, unique_id) values (1, 23, 3007), (1, 24, 30008), (1 ,1 ,30009), (2, 4, 30007), (2 , 5 , 30008), (2 , 1 , 30009), (3 , 6, 30007), (3 , 7, 30008
), (3 , 2 , 30009);
/*select * from Fields;*/
select SUM(remote) from Fields as F where F.unique_id = '30008' and F.id in (select remote from Fields as G where G.unique_id = '30009');
And the ouput was: 29 as desired.
You could use exists
select sum(remote) total
from Fields f
where exists (
select 1 from Fields
where remote = f.id and unique_id = 30009
) and f.unique_id = 30008
I have a table setup as follows:
Key || Code || Date
5 2 2018
5 1 2017
8 1 2018
8 2 2017
I need to retrieve only the key and code where:
Code=2 AND Date > the other record's date
So based on this data above, I need to retrieve:
Key 5 with code=2
Key 8 does not meet the criteria since code 2's date is lower than code 1's date
I tried joining the table on itself but this returned incorrect data
Select key,code
from data d1
Join data d2 on d1.key = d2.key
Where d1.code = 2 and d1.date > d2.date
This method returned data with incorrect values and wrong data.
Perhaps you want this:
select d.*
from data d
where d.code = 2 and
d.date > (select d2.date
from data d2
where d2.key = d.key and d2.code = 1
);
If you just want the key, I would go for aggregation:
select d.key
from data d
group by d.key
having max(case when d2.code = 2 then date end) > max(case when d2.code <> 2 then date end);
use row_number, u can select rows with dates in ascending order. This is based on your sample data, selecting 2 rows
DECLARE #table TABLE ([key] INT, code INT, DATE INT)
INSERT #table
SELECT 5, 2, 2018
UNION ALL
SELECT 5, 2, 2018
UNION ALL
SELECT 8, 1, 2018
UNION ALL
SELECT 8, 2, 2017
SELECT [key], code, DATE
FROM (
SELECT [key], code, DATE, ROW_NUMBER() OVER (
PARTITION BY [key], code ORDER BY DATE
) rn
FROM #table
) x
WHERE rn = 2
Suppose I have a list of values, such as 1, 2, 3, 4, 5 and a table where some of those values exist in some column. Here is an example:
id name
1 Alice
3 Cindy
5 Elmore
6 Felix
I want to create a SELECT statement that will include all of the values from my list as well as the information from those rows that match the values, i.e., perform a LEFT OUTER JOIN between my list and the table, so the result would be like follows:
id name
1 Alice
2 (null)
3 Cindy
4 (null)
5 Elmore
How do I do that without creating a temp table or using multiple UNION operators?
If in Microsoft SQL Server 2008 or later, then you can use Table Value Constructor
Select v.valueId, m.name
From (values (1), (2), (3), (4), (5)) v(valueId)
left Join otherTable m
on m.id = v.valueId
Postgres also has this construction VALUES Lists:
SELECT * FROM (VALUES (1, 'one'), (2, 'two'), (3, 'three')) AS t (num,letter)
Also note the possible Common Table Expression syntax which can be handy to make joins:
WITH my_values(num, str) AS (
VALUES (1, 'one'), (2, 'two'), (3, 'three')
)
SELECT num, txt FROM my_values
With Oracle it's possible, though heavier From ASK TOM:
with id_list as (
select 10 id from dual union all
select 20 id from dual union all
select 25 id from dual union all
select 70 id from dual union all
select 90 id from dual
)
select * from id_list;
the following solution for oracle is adopted from this source. the basic idea is to exploit oracle's hierarchical queries. you have to specify a maximum length of the list (100 in the sample query below).
select d.lstid
, t.name
from (
select substr(
csv
, instr(csv,',',1,lev) + 1
, instr(csv,',',1,lev+1 )-instr(csv,',',1,lev)-1
) lstid
from (select ','||'1,2,3,4,5'||',' csv from dual)
, (select level lev from dual connect by level <= 100)
where lev <= length(csv)-length(replace(csv,','))-1
) d
left join test t on ( d.lstid = t.id )
;
check out this sql fiddle to see it work.
Bit late on this, but for Oracle you could do something like this to get a table of values:
SELECT rownum + 5 /*start*/ - 1 as myval
FROM dual
CONNECT BY LEVEL <= 100 /*end*/ - 5 /*start*/ + 1
... And then join that to your table:
SELECT *
FROM
(SELECT rownum + 1 /*start*/ - 1 myval
FROM dual
CONNECT BY LEVEL <= 5 /*end*/ - 1 /*start*/ + 1) mypseudotable
left outer join myothertable
on mypseudotable.myval = myothertable.correspondingval
Assuming myTable is the name of your table, following code should work.
;with x as
(
select top (select max(id) from [myTable]) number from [master]..spt_values
),
y as
(select row_number() over (order by x.number) as id
from x)
select y.id, t.name
from y left join myTable as t
on y.id = t.id;
Caution: This is SQL Server implementation.
fiddle
For getting sequential numbers as required for part of output (This method eliminates values to type for n numbers):
declare #site as int
set #site = 1
while #site<=200
begin
insert into ##table
values (#site)
set #site=#site+1
end
Final output[post above step]:
select * from ##table
select v.id,m.name from ##table as v
left outer join [source_table] m
on m.id=v.id
Suppose your table that has values 1,2,3,4,5 is named list_of_values, and suppose the table that contain some values but has the name column as some_values, you can do:
SELECT B.id,A.name
FROM [list_of_values] AS B
LEFT JOIN [some_values] AS A
ON B.ID = A.ID