I have to create a materialized view based on data:-
ID Class_Code Student_Name
1 1011 Jatin
2 1012 Pual
3 Patrick
4 1014 Liaba
5 Noah
and i want a materialized view to return
ID Class_Code Student_Name
1 1011 Jatin
2 1012 Pual
3 Not Enrolled Patrick
4 1014 Liaba
5 Not Enrolled Noah
Yes i did some research on google and did not get any thing. CASE WHEN statements return weird results. Please help.
I dont think this is much complexed. You may try this below simple query -
SELECT ID, NVL(Class_Code, 'Not Enrolled') Class_Code, Student_Name
FROM YOUR_MV;
You can try to use the NVL:
NVL(class_code, 'Not Enrolled')
This way, whenever the value for the column CLASS_CODE is NULL, it will populate the void with a "Not Enrolled".
Related
I have a table in oracle that I'm trying to write a query for but having a problem writing it correctly. The data of the table looks like this:
Name
ID
DATE
Shane
1
01JAN2023
Angie
2
02JAN2023
Shane
1
02JAN2023
Austin
3
03JAN2023
Shane
1
03JAN2023
Angie
2
03JAN2023
Tony
4
05JAN2023
What I was trying to come up with was a way to iterate over each day, look at all the records for that day and compare with the rest of the records in the table that came before it and only pull back the first instance of the record based on the ID & Date. The expected output would be:
Name
ID
DATE
Shane
1
01JAN2023
Angie
2
02JAN2023
Austin
3
03JAN2023
Tony
4
05JAN2023
Can anyone tell me what the query should be to accomplish this?
Thank you in advance.
You'll need to convert your date field to a real date so it orders correctly
SELECT name,id,MIN(TO_DATE(date,'DDMONYYYY')) date
FROM table
GROUP BY name,id
Isn't that just
select name, id, min(date_column)
from your_table
group by name, id;
If you don't want to use aggregation, you can use FETCH NEXT ROWS WITH TIES:
SELECT tab.*
FROM tab
ORDER BY ROW_NUMBER() OVER(PARTITION BY Name, Id ORDER BY DATE_)
FETCH NEXT 1 ROWS WITH TIES
Output:
NAME
ID
DATE_
Angie
2
02-JAN-23
Austin
3
03-JAN-23
Shane
1
01-JAN-23
Tony
4
05-JAN-23
Check the demo here.
I have a table TRAVEL with column TRIP_ID as primary key.
SOURCE DATA
TRIP_ID PERSON_NAME DESTINATION SOURCE TRANSACTION_ID TRIP_COUNT
100 Mike London Zurich 1000B112 1
101 Mike Paris Capetown 1000B112 1
102 Mike Moscow Madrid 1000B112 1
103 John Delhi Moscow 1100A110 1
104 John Toronto Zurich 1100A110 1
105 Mary Chennai Madrid 1100A111 1
106 Mary Berlin Zurich 1100A111 1
EXPECTED RESULTS:
when I do select * from TRAVEL where TRANSACTION_ID = 1100A111 it returns below two rows as below .
so I want my data to be categorized based on the transaction_ID on a run time.I dont want to hardcode the value for transaction-ID each time as above but i want to group it in such a way that it should fetch me the above expected results.I mean it should return all the data which are corresponding to the TransactionID in the table and it should not sum up the TRIP COUNT.It should return me the rows as below in my table.I am ok to create view .Please suggest
TRIP_ID PERSON_NAME DESTINATION SOURCE TRANSACTION_ID TRIP_COUNT
105 Mary Chennai Madrid 1100A111 1
106 Mary Berlin Zurich 1100A111 1
Can someone suggest a query in ORACLE to handle this ? I donot want to hardcode transaction ID
Regards
Sameer
Let's say i have a table structure like this :
ID | Name | SCHOOLNAME | CODESCHOOL
1 DARK Kindergarten 123 1
2 DARK Kindergarten 111 1
3 Knight NY University 3
4 Knight LA Senior HS 2
5 JOHN HARVARD 3
so, how to diplay all of the data above into like this :
ID | Name | SCHOOLNAME | CODESCHOOL
1 DARK Kindergarten 123 1
3 Knight NY University 3
5 JOHN HARVARD 3
my purpose is want to display data with the max of codeschool, but when i tried with my query below :
SELECT NAME, SCHOOLNAME, MAX(CODESCHOOL) FROM TABLE GROUP BY NAME, SCHOOLNAME
but the result is just like this :
ID | Name | SCHOOLNAME | CODESCHOOL
1 DARK Kindergarten 123 1
2 DARK Kindergarten 111 1
3 Knight NY University 3
4 Knight LA Senior HS 2
5 JOHN HARVARD 3
maybe it caused by the GROUP BY SCHOOLNAME, when i tried to not select SCHOOLNAME, the data displayed just like what i expected, but i need the SCHOOLNAME field for search condition in my query
hope you guys can help me out of this problem
any help will be appreciated
thanks
Using some wacky joins you can get a functional get max rows per category query.
What you essentially need to do is to join the table to itself and make sure that the joined values only contain the top values for the CODESCHOOL column.
I've also added a :schoolname parameter because you wanted to search by schoolname
Example:
SELECT
A.*
FROM
TABLE1 A
LEFT OUTER JOIN TABLE1 B ON B.NAME = A.NAME
AND B.CODESCHOOL < A.CODESCHOOL
WHERE
B.CODESCHOOL IS NULL AND
(
(A.SCHOOLNAME = :SCHOOLNAME AND :SCHOOLNAME IS NOT NULL) OR
(:SCHOOLNAME IS NULL)
);
this should create this output, note that dark has 2 outputs because it has 2 rows with the same code school which is the max in the dark "category"/name.
ID|NAME |SCHOOLNAME |CODESCHOOL
--| -----|----------------|----------
4|Knight|LA Senior HS | 2
5|JOHN |HARVARD | 3
2|DARK |Kindergarten 111| 1
1|DARK |Kindergarten 123| 1
It's not the most effective query but it should be more than good enough as a starting point.
Sidenote: I've been blatantly stealing this logic for a while from https://www.xaprb.com/blog/2007/03/14/how-to-find-the-max-row-per-group-in-sql-without-subqueries/
I am using an analytical window function ROW_NUMBER().
This will group (or partition) by NAME then select the top 1 CODESCHOOL in DESC order.
Select NAME,
SCHOOLNAME,
CODESCHOOL
From (
Select NAME,
SCHOOLNAME,
CODESCHOOL,
ROW_NUMBER() OVER (PARTITION BY NAME ORDER BY CODESCHOOL DESC) as rn
from myTable)
Where rn = 1;
Suppose I have 2 tables as shown below. Now, if I want to achieve result which sql will give using, insert into B where id not in(select id from A)
which will insert 3 George in Table B.
How to implement this in hive?
Table A
id name
1 Rahul
2 Keshav
3 George
Table B
id name
1 Rahul
2 Keshav
4 Yogesh
NOT IN in the WHERE clause with uncorrelated subqueries is supported since Hive 0.13 which was released more than 3 years ago, on 21 April, 2014.
select * from A where id not in (select id from B where id is not null);
+----+--------+
| id | name |
+----+--------+
| 3 | George |
+----+--------+
On earlier versions the column of the outer table should be qualified with the table name/alias.
hive> select * from A where id not in (select id from B where id is not null);
FAILED: SemanticException [Error 10249]: Line 1:22 Unsupported SubQuery Expression 'id': Correlating expression cannot contain unqualified column references.
hive> select * from A where A.id not in (select id from B where id is not null);
OK
3 George
P.s.
When using NOT IN you should add is not null to the inner query, unless you are 100% sure that the relevant column does not contain null values.
One null value is enough to cause your query to return no results.
I have two tables, let's call them PERSON and NAME.
PERSON
person_id
dob
NAME
name_id
person_id
name
And let's say that the NAME table has data like:
name_id person_id name
1 1 Joe
2 1 Fred
3 1 Sam
4 2 Jane
5 2 Kim
I need a query (Oracle 10g) that will return
name_id names
1 Joe, Fred, Sam
2 Jane, Kim
Is there a simple way to do this?
Update:
According to the article that figs was kind enough to provide, starting in 9i you can do:
SELECT wmsys.wm_concat(dname) departments FROM dept;
For this example, the answer becomes:
SELECT name_id, wmsys.wm_concat(name) from names group by name_id
The short answer is to use a PL/SQL function. For more details, have a look in this post.