Is it possible to transform tuple into columns in ClickHouse?
SELECT tuple(1,'a') gives
| tuple(1,'a') |
–-|--------------|
0 | (1,'a') |
How to transform it into result of two columns?
| 0 | 1 |
–-|---------|
0 | 1 | 'a' |
(1, 'a').1
.tuple_element_index or function tupleElement
SELECT
(1, 'a').1,
(1, 'a').2
/*
┌─tupleElement(tuple(1, 'a'), 1)─┬─tupleElement(tuple(1, 'a'), 2)─┐
│ 1 │ a │
└────────────────────────────────┴────────────────────────────────┘
*/
Related
If I had a table with two columns
Id
json_data
1
[1, 10, 11]
2
[]
I could easily query the results using
SELECT M1.Id
FROM MyTable M1
WHERE Id NOT EXISTS (
SELECT 1 FROM MyTable M2, (JSON_TABLE(M2.JsonData, '$[*]'
ERROR ON ERROR NULL ON EMPTY NULL ON MISMATCH
COLUMNS(
Id NVARCHAR2(20) PATH '$'))) JT
WHERE JT.Id = M1.Id)
Now how do I index this column so the query is not doint a full table scan?
MULTIVALUE indexes are used (I believe) for only JSON_EXISTS queries like this one
SELECT Id
FROM MyTable WHERE NOT JSON_EXISTS(JsonData, '$?(# == 1)')
but I can't use this function for non constant values such as M1.Id
MULTIVALUE INDEX is available only in 21c and the array should be a field of a record, and the column must be JSON, it doesn't work with a CLOB with a CHECK constraint "IS JSON".
https://asktom.oracle.com/pls/apex/f?p=100:11:0::::P11_QUESTION_ID:9545758700346721260
create table t_test_ixjs (
id number(10,0),
json_data JSON
);
insert into t_test_ixjs(id,json_data) values(1,'{ "a" : [1, 10, 11] }') ;
insert into t_test_ixjs(id,json_data) values(2,'{ "a" : [] }') ;
create multivalue index ix_test_json_data on t_test_ixjs t ( t.json_data.a.number() );
with vals(d) as (
select 1 from dual
)
SELECT *
FROM vals v,
t_test_ixjs WHERE JSON_EXISTS(json_data, '$.a?(# == $d)' PASSING v.d AS "d")
;
Plan hash value: 1205791918
---------------------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 20513 | 2 (0)| 00:00:01 |
| 1 | TABLE ACCESS BY INDEX ROWID BATCHED| T_TEST_IXJS | 1 | 20513 | 2 (0)| 00:00:01 |
| 2 | HASH UNIQUE | | 1 | 20513 | | |
|* 3 | INDEX RANGE SCAN (MULTI VALUE) | IX_TEST_JSON_DATA | 1 | | 1 (0)| 00:00:01 |
---------------------------------------------------------------------------------------------------------
TABLE: HIST
CUSTOMER MONTH PLAN
1 1 A
1 2 B
1 2 C
1 3 D
If I query:
select h.*, lead(plan) over (partition by customer order by month) np from HIST h
I get:
CUSTOMER MONTH PLAN np
1 1 A B
1 2 B C
1 2 C D
1 3 D (null)
But I wanted
CUSTOMER MONTH PLAN np
1 1 A B
1 2 B D
1 2 C D
1 3 D (null)
Reason being, next month to 2 is 3, with D. I'm guessing partition by customer order by month doesn't work the way I thought.
Is there a way to achieve this in Oracle 12c?
One way to do it is to use RANGE partitioning with the MIN analytic function. Like this:
select h.*,
min(plan) over
(partition by customer
order by month
range between 1 following and 1 following) np
from HIST h;
+----------+-------+------+----+
| CUSTOMER | MONTH | PLAN | NP |
+----------+-------+------+----+
| 1 | 1 | A | B |
| 1 | 2 | B | D |
| 1 | 2 | C | D |
| 1 | 3 | D | |
+----------+-------+------+----+
When you use RANGE partitioning, you are telling Oracle to make the windows based on the values of the column you are ordering by rather than making the windows based on the rows.
So, e.g.,
ROWS BETWEEN 1 following and 1 following
... will make a window containing the next row.
RANGE BETWEEN 1 following and 1 following
... will make a window containing all the rows having the next value for month.
UPDATE
If it is possible that some values for MONTH might be skipped for a given customer, you can use this variant:
select h.*,
first_value(plan) over
(partition by customer
order by month
range between 1 following and unbounded following) np
from h
+----------+-------+------+----+
| CUSTOMER | MONTH | PLAN | NP |
+----------+-------+------+----+
| 1 | 1 | A | B |
| 1 | 3 | B | D |
| 1 | 3 | C | D |
| 1 | 4 | D | |
+----------+-------+------+----+
You can use LAG/LEAD twice. The first time to check for duplicate months and to set the value to NULL in those months and the second time use IGNORE NULLS to get the next monthly value.
It has the additional benefit that if months are skipped then it will still find the next value.
SQL Fiddle
Oracle 11g R2 Schema Setup:
CREATE TABLE HIST ( CUSTOMER, MONTH, PLAN ) AS
SELECT 1, 1, 'A' FROM DUAL UNION ALL
SELECT 1, 2, 'B' FROM DUAL UNION ALL
SELECT 1, 2, 'C' FROM DUAL UNION ALL
SELECT 1, 3, 'D' FROM DUAL UNION ALL
SELECT 2, 1, 'E' FROM DUAL UNION ALL
SELECT 2, 1, 'F' FROM DUAL UNION ALL
SELECT 2, 3, 'G' FROM DUAL UNION ALL
SELECT 2, 5, 'H' FROM DUAL;
Query 1:
SELECT CUSTOMER,
MONTH,
PLAN,
LEAD( np ) IGNORE NULLS OVER ( PARTITION BY CUSTOMER ORDER BY MONTH, PLAN, ROWNUM ) AS np
FROM (
SELECT h.*,
CASE MONTH
WHEN LAG( MONTH ) OVER ( PARTITION BY CUSTOMER ORDER BY MONTH, PLAN, ROWNUM )
THEN NULL
ELSE PLAN
END AS np
FROM hist h
)
Results:
| CUSTOMER | MONTH | PLAN | NP |
|----------|-------|------|--------|
| 1 | 1 | A | B |
| 1 | 2 | B | D |
| 1 | 2 | C | D |
| 1 | 3 | D | (null) |
| 2 | 1 | E | G |
| 2 | 1 | F | G |
| 2 | 3 | G | H |
| 2 | 5 | H | (null) |
Just so that it is listed here as an option for Oracle 12c (onward), you can use an apply operator for this style of problem
select
h.customer, h.month, h.plan, oa.np
from hist h
outer apply (
select
h2.plan as np
from hist h2
where h.customer = h.customer
and h2.month > h.month
order by month
fetch first 1 rows only
) oa
order by
h.customer, h.month, h.plan
I don't know of any Oracle 12c public fiddles so, an example in SQL Server can be found here: http://sqlfiddle.com/#!18/cd95e/1
| customer | month | plan | np |
|----------|-------|------|--------|
| 1 | 1 | A | C |
| 1 | 2 | B | D |
| 1 | 2 | C | D |
| 1 | 3 | D | (null) |
I want to fetch records from oracle DB where column value is NULL. Also i am using unpivot in my query. Somehow NULL values are not getting selected because of unpivot keyword. Can you please help me about how to get rows for the same when using unpivot.
EDIT:
SELECT a.emp_id, a.emp_dept, b.emp_location
FROM employee a,
location b UNPIVOT (emp_id
FOR dummy_id
IN (emp_id AS 'EMP_ID', last_date AS 'LAST_DATE'))
WHERE emp_id = 123 AND b.emp_loc_id = 'india' AND b.location IS NULL;
Use UNPIVOT INCLUDE NULLS:
SQL Fiddle
Oracle 11g R2 Schema Setup:
CREATE TABLE test ( id, a, b, c, d ) AS
SELECT 1, 1, 2, 3, 4 FROM DUAL UNION ALL
SELECT 2, 1, NULL, 3, NULL FROM DUAL;
Query 1:
SELECT *
FROM test
UNPIVOT INCLUDE NULLS ( value FOR name IN ( a, b, c, d ) )
Results:
| ID | NAME | VALUE |
|----|------|--------|
| 1 | A | 1 |
| 1 | B | 2 |
| 1 | C | 3 |
| 1 | D | 4 |
| 2 | A | 1 |
| 2 | B | (null) |
| 2 | C | 3 |
| 2 | D | (null) |
I am using Oracle.
I am currently working one 2 tables which both have the same column names. Is there any way in which I can combine the 2 tables together as they are?
Simple example to show what I mean:
TABLE 1:
| COLUMN 1 | COLUMN 2 | COLUMN 3 |
----------------------------------------
| a | 1 | w |
| b | 2 | x |
TABLE 2:
| COLUMN 1 | COLUMN 2 | COLUMN 3 |
----------------------------------------
| c | 3 | y |
| d | 4 | z |
RESULT THAT I WANT:
| COLUMN 1 | COLUMN 2 | COLUMN 3 |
----------------------------------------
| a | 1 | w |
| b | 2 | x |
| c | 3 | y |
| d | 4 | z |
Any help would be greatly appreciated. Thank you in advance!
You can use the union set operator to get the result of two queries as a single result set:
select column1, column2, column3
from table1
union all
select column1, column2, column3
from table2
union on its own implicitly removes duplicates; union all preserves them. More info here.
The column names don't need to be the same, you just need the same number of columns with the same datatpes, in the same order.
(This is not what is usually meant by a join, so the title of your question is a bit misleading; I'm basing this on the example data and output you showed.)
This is a bit hard to explain in words ... I'm trying to calculate a sum of grouped distinct values in a matrix. Let's say I have the following data returned by a SQL query:
------------------------------------------------
| Group | ParentID | ChildID | ParentProdCount |
| A | 1 | 1 | 2 |
| A | 1 | 2 | 2 |
| A | 1 | 3 | 2 |
| A | 1 | 4 | 2 |
| A | 2 | 5 | 3 |
| A | 2 | 6 | 3 |
| A | 2 | 7 | 3 |
| A | 2 | 8 | 3 |
| B | 3 | 9 | 1 |
| B | 3 | 10 | 1 |
| B | 3 | 11 | 1 |
------------------------------------------------
There's some other data in the query, but it's irrelevant. ParentProdCount is specific to the ParentID.
Now, I have a matrix in the MS Report Designer in which I'm trying to calculate a sum for ParentProdCount (grouped by "Group"). If I just add the expression
=Sum(Fields!ParentProdCount.Value)
I get a result 20 for Group A and 3 for Group B, which is incorrect. The correct values should be 5 for group A and 1 for group B. This wouldn't happen if there wasn't ChildID involved, but I have to use some other child-specific data in the same matrix.
I tried to nest FIRST() and SUM() aggregate functions but apparently it's not possible to have nested aggregation functions, even when they have scopes defined.
I'm pretty sure there is some way to calculate the grouped distinct sum without needing to create another SQL query. Anyone got an idea how to do that?
Ok I got this sorted out by adding a ROW_NUMBER() function my SQL query:
SELECT Group, ParentID, ROW_NUMBER() OVER (PARTITION BY ParentID ORDER BY ChildID ASC) AS Position, ChildID, ParentProdCount FROM Table
and then I replaced the SSRS SUM function with
=SUM(IIF(Position = 1, ParentProdCount.Value, 0))
Put a grouping over the ParentID and use a summation over that group,
eg:
if group over ParentID = "ParentIDGroup"
then
column sum of ParentPrdCount = SUM(Fields!ParentProdCount.Value,"ParentIDGroup")