I have a (now thoroughly derived) CTE:
feature_id | function_id | group_id | subgroup_id | type_id
1 1 null 1 null
1 1 null null 14
2 1 null 5 null
2 1 null null 21
3 1 null 7 null
3 1 null null 5
I am trying to collate the rows together using this:
select C1.feature_id, C1.function_Id, C2.Group_ID, C3.Subgroup_ID, C4.Type_id
from CTE C1
left join CTE C2
on C1.feature_id = C2.feature_id
and c1.function_id = c2.function_id
and c2.group_id is not null
left join CTE C3
on C1.feature_id = C3.feature_id
and c1.function_id = c3.function_id
and c3.subgroup_id is not null
left join CTE C4
on C1.feature_id = C4.feature_id
and c1.function_id = c4.function_id
and c4.type_id is not null
This gives me 0 rows...
To validate, I ran:
select *
from CTE C1
236 rows selected
Can anyone help? Surely the rows from C1 should be coming back...
EDIT: Fixed it with the Oracle syntax:
select C1.feature_id, C1.function_Id, C2.Group_ID, C3.Subgroup_ID, C4.Type_id
from CTE C1, CTE C2, CTE C3, CTE C4
where C1.feature_id = C2.feature_id(+)
and c1.function_id = c2.function_id(+)
and C2.group_id(+) is not null
...
(I hate the oracle syntax)
Ok, solved it... Fixed it with the Oracle syntax:
select C1.feature_id, C1.function_Id, C2.Group_ID, C3.Subgroup_ID, C4.Type_id
from CTE C1, CTE C2, CTE C3, CTE C4
where C1.feature_id = C2.feature_id(+)
and c1.function_id = c2.function_id(+)
and C2.group_id(+) is not null
...
(I hate the oracle syntax)
Related
After a join of the same table, I have a result like this:
c1 c2 count
A B 5
A C 4
B A 2
B C 2
C A 1
Now, the numbers should been added, if c1 and c2 are switched, like this:
c1 c2 count
A B 7
A C 5
B C 2
How can this be done with a query?
Using a left join to self join the table on inverse positions and returning those where c1 is less than c2, or it had no matching row. Using coalesce to add 0 when the left joined count is null.
select
t.c1
, t.c2
, t.count + coalesce(s.count,0) as count
from t
left join t as s
on t.c1 = s.c2
and t.c2 = s.c1
where t.c1 < t.c2 or s.c1 is null
rextester demo in sql server: http://rextester.com/VBQI62112
returns:
+----+----+-------+
| c1 | c2 | count |
+----+----+-------+
| A | B | 7 |
| A | C | 5 |
| B | C | 2 |
+----+----+-------+
Many databases support least() and greatest(). If they are available, you can do:
select least(c1, c2) as c1, greatest(c1, c2) as c2, sum(count) as cnt
from (<your query here>) t
group by least(c1, c2), greatest(c1, c2);
In databases that don't support these functions, you can use case.
Note: The semantics of least() and greatest() return NULL if either column is NULL, so you may need to be careful if either value could be NULL.
Perhaps join the output c1,c2 with the same c2,c1?
select t1.c1
,t1.c2
,sum(coalesce(t1.count,0), coalesce(t2.count,0))
from table t1
left join table t2
on t1.c1 = t2.c2
and t1.c2 = t2.c1
group by t1.c1, t1.c2
having t1.c1 < t1.c2
SELECT t.c1
, t.c2
, t.cnt + CASE WHEN s.cnt IS NULL THEN 0 ELSE s.cnt END as cnt
FROM t
LEFT JOIN
t as s
ON t.c1 = s.c2
AND t.c2 = s.c1
WHERE t.c1 < t.c2;
I have a table t1:
c1 | c2 | c3| c4
1 1 1 A
1 1 2 B
1 1 3 C
1 1 4 D
1 1 4 E
1 1 4 F
2 2 1 A
2 2 2 A
2 2 3 A
I want to select the last row of each c1, c2 pair. So (1,1,4,F) and (2,2,3,A) in this case. My idea is to do something like this:
create table t2 as
select *, row_number() over (partition by c1, c2 order by c3) as rank
from t1
create table t3 as
select a.c1, a.c2, a.c3, a.c4
from t2 a
inner join
(select c1, c2, max(rank) as maxrank
from t2
group by c1, c2
)
on a.c1=b.c1 and a.c2=b.c1
where a.rank=b.maxrank
Would this work? (Having environment issues so can't test myself)
Just use a subquery:
select t1.*
from (select t1.*, row_number() over (partition by c1, c2 order by c3 desc) as rank
from t1
) t1
where rank = 1;
Note the use of desc for the order by.
Let's say I have a table with an ID column, and several property columns
MyTable (ID, PI, P2, P3, P4)
ID P1 P2 P3 P4
1 A1 B C1 D1
2 C1 C2 B NULL
3 C2 Z NULL NULL
4 X A1 C1 NULL
So, I need to write a query to find out how many distinct property values out there, no matter in which column they are.
Value Count
A1 2
B 2
C1 3
C2 2
X1 1
...
I think I can get this by using UNPIVOT (correct me, if I am wrong)
Now, how can I get similar count but grouped by a number of non-null values in the row (the count of non-null values per row may, or may not include key columns, doesn't matter), i.e. output like this:
Value NonNullCount Count
A1 3 1
A1 4 1
B 3 1
B 4 1
C1 2 3
C1 4 1
C2 3 1
C2 2 1
...
Here is one method, using cross apply for the unpivot:
select vals.p, t.NonNullCount, count(*)
from (select t.*,
((case when p1 is not null then 1 else 0 end) +
(case when p2 is not null then 1 else 0 end) +
(case when p3 is not null then 1 else 0 end) +
(case when p4 is not null then 1 else 0 end)
) as NonNullCount
from table t
) t cross apply
(values (p1), (p2), (p3), (p4)) vals(p)
where vals.p is not null
group by vals.p, t.NonNullCount;
I have a table similar to below:
C1 C2 C3
A 5 0
A 15 0
A 2 0
B 5 0
B 8 0
Result table updates C3 with 1 for mac value of C2 group by C1
C1 C2 C3
A 5 0
A 15 1
A 2 0
B 5 0
B 8 1
For SQL Server 2005+:
;WITH CTE AS
(
SELECT *,
MAX(C2) OVER(PARTITION BY C1) MaxC2
FROM YourTable
)
UPDATE CTE
SET C3 = CASE WHEN MaxC2 = C2 THEN 1 ELSE 0 END
Supossing table is named table_name
UPDATE t1 SET t1.C3 = 1
FROM table_name as t1 INNER JOIN (
SELECT C1, MAX(C2) AS C2 FROM table_name GROUP BY C1
) AS t2 ON t1.C1 = t2.C1 AND t1.C2 = t2.C2
I am trying to build a query which will give me unique rows. Details:-
Table 1 (F1, F2 are the columns)
F1 F2
1 A1
2 A2
3 A3
4 A4
Table 2 (F3,F4 are the columns)
F3 F4
1 B1
1 B11
2 B2
2 B22
My Query (Incorrect)
select rrn(A), F1,F2,F3,F4 from rush2hem1.T1 A left outer join rush2hem1.T2 B on A.F1=B.F3
This gives me below output which is not what I am looking for:-
RRN F1 F2 F3 F4
1 1 A1 1 B1
1 1 A1 1 B11
2 2 A2 2 B2
2 2 A2 2 B22
3 3 A3 (null) (null)
4 4 A4 (null) (null)
Expected output that I am building query for is:-
RRN F1 F2 F3 F4
1 1 A1 1 B1
2 2 A2 2 B2
3 3 A3 (null) (null)
4 4 A4 (null) (null)
Please let me know if you have any suggestions.
This problem could be solved differently in different RDBMS. In any case, you have to specify which one record from Table2 do you want to get (by order by clause)
If your database have window function row_number(), you can use it like this:
select
F1, F2, F3, F4
from (
select
T1.F1, T1.F2, T2.F3, T2.F4,
-- order by specifying which row you would get from Table2
row_number() over(partition by T1.F1 order by T2.F4) as rn
from Table1 as T1
left outer join Table2 as T2 on T2.F3 = T1.F1
) as cte
where rn = 1;
In SQL Server, you can use outer apply:
select
T1.F1, T1.F2, T2.F3, T2.F4
from Table1 as T1
outer apply (
select top 1 T2.F3, T2.F4
from Table2 as T2
where T2.F3 = T1.F1
order by T2.F3 asc -- This is important line
) as T2;
In PostgreSQL, you can use distinct on syntax:
select distinct on (T1.F1)
T1.F1, T1.F2, T2.F3, T2.F4
from Table1 as T1
left outer join Table2 as T2 on T2.F3 = T1.F1
order by T1.F1, T2.F4; -- sort by F4 is important
SQL Server sqlfiddle demo
PostgreSQL sqlfiddle demo
Not tested, It's a SQL server version.
select rrn(A), F1,F2,F3,F4
from
(
select rrn(A), F1,F2,F3,F4,row_number() over(partition by RRN order by RRN) as rn
from rush2hem1.T1 A left outer join rush2hem1.T2 B
on A.F1=B.F3
) as dt
where dt.rn = 1
Please check the result with OUTER APPLY
SELECT
*
FROM
Table1 a
OUTER APPLY
(SELECT
TOP 1 *
FROM
Table2 b
WHERE a.F1=b.F3)c