I am trying to achieve the Expected Result which is at the end of my post from two data sets. I am using left join which is not helping me to get my expected result. I would like to get all the matched and unmatched records from both tables.
Query used to create and retrieve dataset and my current result set are below:
select
a.id, a.name, a.rev, isnull(b.conv, 0) as conv
from
(select
1 as id, 'A' as name, 2 as rev, 0 as conv
union all
select
2 as id, 'B' as name, 1 as rev, 0 as conv) a
left join
(select
1 as id, 'A' as name, 0 AS rev, 2 as conv
union all
select
3 as id, 'C' as name, 0 as rev, 3 as conv) b on a.id = b.id
Current result from above query using left join:
id name rev conv
---------------------
1 A 2 2
2 B 1 0
Expected result:
id name rev conv
--------------------
1 A 2 2
2 B 1 0
3 C 0 3
Use FULL JOIN instead:
SELECT ISNULL(a.id,b.id) id,
ISNULL(a.name,b.name) name,
ISNULL(a.rev,0) rev,
ISNULL(b.conv,0) conv
FROM ( SELECT 1 as id , 'A' as name , 2 as rev, 0 as conv
UNION ALL
SELECT 2 as id , 'B' as name, 1 as rev, 0 as conv) a
FULL JOIN ( SELECT 1 as id , 'A' as name, 0 AS rev, 2 as conv
UNION ALL
SELECT 3 as id , 'C' as name, 0 as rev, 3 as conv) b
ON a.id = b.id
ORDER BY ISNULL(a.id,b.id);
You should try with FULL OUTER JOIN, this combines the results of both LEFT and RIGHT joins.
Sintax:
SELECT column_name(s)
FROM
table1 FULL OUTER JOIN table2
ON
table1.column_name = table2.column_name;
I hope it helps!
Related
I have a RELATION table
NUM1 | NUM2 | NUM3
-- --- -----
1 2 3
2 4 5
3 4 null
3 4 null
and the actual INFO table where NUM is primary key.
NUM | A_LOT_OF_OTHER_INFO
--- --------------------
1 asdff
2 werwr
3 erert
4 ghfgh
5 cvbcb
I want to create a view to see the count of the NUM that appeared in any of the NUM1, NUM2, NUM3 of the RELATION table.
MY_VIEW
NUM | A_LOT_OF_OTHER_INFO | TOTAL_COUNT
--- -------------------- ------------
1 asdff 1
2 werwr 2
3 erert 3
4 ghfgh 3
5 cvbcb 1
I can do this by doing three selects from RELATION table and UNION them, but I do not want to use UNION because the tables have a lot of records, MY_VIEW is already large enough and I am looking for a better way to join to the RELATION table in the view. Can you suggest a way?
What i would try is to unpivot the relation table.
After that join the info table on the values and count the number of times the val gets repeated.
create table relation(num1 int,num2 int, num3 int);
insert into relation values(1,2,3);
insert into relation values(2,4,5);
insert into relation values(3,4,null);
create table info(num int, a_lot_of_other_info varchar2(100));
insert into info
select 1,'asdff' from dual union all
select 2,'werwr' from dual union all
select 3,'erert' from dual union all
select 4,'ghfgh' from dual union all
select 5,'cvbcb' from dual
select a.num
,max(a_lot_of_other_info) as a_lot_of_other_info
,count(*) as num_of_times
from info a
join (select val
from relation a
unpivot(val for x in (num1,num2,num3))
)b
on a.num=b.val
group by a.num
order by 1
I would suggest a correlated subquery:
select i.*,
(select ((case when r.num1 = i.num then 1 else 0 end) +
(case when r.num2 = i.num then 1 else 0 end) +
(case when r.num3 = i.num then 1 else 0 end)
)
from relation r
where i.num in (r.num1, r.num2, r.num3)
) as total_count
from info i;
If performance is a consideration, it might be faster to use left joins:
select i.*,
((case when r1.num1 is not null then 1 else 0 end) +
(case when r2.num1 is not null then 1 else 0 end) +
(case when r3.num1 is not null then 1 else 0 end)
) as total_count
from info i left join
relation r1
on i.num = r1.num1 left join
relation r2
on i.num = r2.num2 left join
relation r3
on i.num = r3.num3;
In particular, this will make optimal use of three separate indexes on relation: relation(num1), relation(num2), and relation(num3).
It seems what you want is UNPIVOT. Perhaps easiest to do with a cross join in this case:
select NUM, count(*) as TOTAL_COUNT
from (
select decode(column_value, 1, NUM1, 2, NUM2, 3, NUM3) as NUM
from RELATION cross join table(sys.odcinumberlist(1,2,3))
)
group by NUM
;
Then join this to the second table; the join part is really irrelevant here.
I have following table
ID Name Stage
1 A 1
1 B 2
1 C 3
1 A 4
1 N 5
1 B 6
1 J 7
1 C 8
1 D 9
1 E 10
I need output as below with parameters A and N need to select closest rows where difference between stage is smallest
ID Name Stage
1 A 4
1 N 5
I need to select rows where difference between stage is smallest
This query can make use of an index on (name, stage) efficiently:
WITH cte AS (
SELECT TOP 1
a.id AS a_id, a.name AS a_name, a.stage AS a_stage
, n.id AS n_id, n.name AS n_name, n.stage AS n_stage
FROM tbl a
CROSS APPLY (
SELECT TOP 1 *, stage - a.stage AS diff
FROM tbl
WHERE name = 'N'
AND stage >= a.stage
ORDER BY stage
UNION ALL
SELECT TOP 1 *, a.stage - stage AS diff
FROM tbl
WHERE name = 'N'
AND stage < a.stage
ORDER BY stage DESC
) n
WHERE a.name = 'A'
ORDER BY diff
)
SELECT a_id AS id, a_name AS name, a_stage AS stage FROM cte
UNION ALL
SELECT n_id, n_name, n_stage FROM cte;
SQL Server uses CROSS APPLY in place of standard-SQL LATERAL.
In case of ties (equal difference) the winner is arbitrary, unless you add more ORDER BY expressions as tiebreaker.
dbfiddle here
This solution works, if u know the minimum difference is always 1
SELECT *
FROM myTable as a
CROSS JOIN myTable as b
where a.stage-b.stage=1;
a.ID a.Name a.Stage b.ID b.Name b.Stage
1 A 4 1 N 5
Or simpler if u don't know the minimum
SELECT *
FROM myTable as a
CROSS JOIN myTable as b
where a.stage-b.stage in (SELECT min (a.stage-b.stage)
FROM myTable as a
CROSS JOIN myTable as b)
In PostgreSQL, how can I merge multiple columns into one column with multiple rows?
The columns are all boolean, so I want to:
Filter for true values only
Replace the true value (1) with the name of the column (A, B or C)
I have this table:
ID | A | B | C
1 0 1 0
2 1 1 0
3 0 0 1
4 1 0 1
5 1 0 0
6 0 1 1
I want to get this table:
ID | Letter
1 B
2 A
2 B
3 C
4 A
4 C
5 A
6 B
6 C
I think you need something like this:
SELECT ID, 'A' as Letter FROM table WHERE A=1
UNION ALL
SELECT ID, 'B' as Letter FROM table WHERE B=1
UNION ALL
SELECT ID, 'C'as Letter FROM table WHERE C=1
ORDER BY ID, Letter
SELECT ID,
(CASE
WHEN TABLE.A = 1 then 'A'
WHEN TABLE.B = 1 then 'B'
WHEN TABLE.C = 1 then 'C'
ELSE NULL END) AS LETTER
from TABLE
You may try this.
insert into t2 select id, 'A' from t1 where A=1;
insert into t2 select id, 'B' from t2 where B=1;
insert into t2 select id, 'C' from t3 where C=1;
If you care about the order, then you can do this.
insert into t3 select id, letter from t2 order by id, letter;
W/o UNION
You can use a single query to get the desired output.Real time example
select id
,regexp_split_to_table((
concat_ws(',', case
when a = 0
then null
else 'a'
end, case
when b = 0
then null
else 'b'
end, case
when c = 0
then null
else 'c'
end)
), ',') l
from c1;
regexp_split_to_table() & concat_ws()
I have the following query below which works. However it is return duplicates which I don't understand.
The first three nested queries return no duplicates so I don't understand why the end result has duplicates sedols?
;with b as
(
select sedol, wgt from myTbl
where name = 'B'
), j as
(
select sedol, wgt from myTbl
where name = 'J'
), s as
(
select sedol, wgt from myTbl
where name = 'S'
), hlds as
(
select coalesce(b.sedol, j.sedol, s.sedol) sedol, isnull(b.wgt,0) bw, isnull(j.wgt,0) jw, isnull(s.wgt,0) sw
from b full outer join j on b.sedol = j.sedol
full outer join s on b.sedol = s.sedol
)
select hlds.* from hlds
order by sedol
sample data
myTbl
sedol name wgt
abc b 1
abc j 2
abc s 3
def j 2
def s 4
current result
abc 1 2 3
def 0 2 0
def 0 0 4
should be
abc 1 2 3
def 0 2 4
Lets improve this query and save the joins with conditional aggregation:
SELECT t.sedol,
MAX(CASE WHEN t.name = 'B' THEN t.wgt END) as [b],
MAX(CASE WHEN t.name = 'J' THEN t.wgt END) as [j],
MAX(CASE WHEN t.name = 'S' THEN t.wgt END) as [s]
FROM YourTable t
GROUP BY t.sedol
I have two result sets that look approximately like this:
Id Name Count
1 Asd 1
2 Sdf 4
3 Dfg 567
4 Fgh 23
But the Count column data is different for the second one and I would like both to be displayed, about like this:
Id Name Count from set 1 Count from set two
1 Asd 1 15
2 Sdf 4 840
3 Dfg 567 81
4 Fgh 23 9
How can I do this in SQL (with union if possible)?
My current SQL, hope this will better explain what I want to do:
(SELECT Id, Name, COUNT(*) FROM Customers where X)
union
(SELECT Id, Name, COUNT(*) FROM Customers where Y)
select *
from
(
SELECT 'S1' as dataset, Id, Name, COUNT(*) as resultcount FROM Customers where X
union
SELECT 'S2',Id, Name, COUNT(*) FROM Customers where Y
) s
pivot
(sum(resultcount) for dataset in (s1,s2)) p
You can do something like:
;WITH Unioned
AS
(
SELECT 'Set1' FromWhat, Id, Name FROM Table1
UNION ALL
SELECT 'Set2', Id, Name FROM Table2
)
SELECT
Id,
Name,
SUM(CASE FromWhat WHEN 'Set1' THEN 1 ELSE 0 END) 'Count from set 1',
SUM(CASE FromWhat WHEN 'Set2' THEN 1 ELSE 0 END) 'Count from set 2'
FROM Unioned
GROUP BY Id, Name;
SQL Fiddle Demo