oracle: grouping on merged columns - oracle10g

I have a 2 tables FIRST
id,rl_no,adm_date,fees
1,123456,14-11-10,100
2,987654,10-11-12,30
3,4343,14-11-17,20
and SECOND
id,rollno,fare,type
1,123456,20,bs
5,634452,1000,bs
3,123456,900,bs
4,123456,700,bs
My requirement is twofold,
1, i first need to get all columns from both tables with common rl_no. So i used:
SELECT a.ID,a.rl_no,a.adm_date,a.fees,b.rollno,b.fare,b.type FROM FIRST a
INNER JOIN
SECOND b ON a.rl_no = b.rollno
The output is like this:
id,rl_no,adm_date,fees,rollno,fare,type
1,123456,14-11-10,100,123456,20,bs
1,123456,10-11-12,100,123456,900,bs
1,123456,14-11-17,100,123456,700,bs
2,Next i wanted to get the sum(fare) of those rollno that were common between the 2 tables and also whose fare >= fees from FIRST table group by rollno and id.
My query is:
SELECT x.ID,x.rl_no,,x.adm_date,x.fees,x.rollno,x.type,sum(x.fare) as "fare" from (SELECT a.ID,a.rl_no,a.adm_date,a.fees,b.rollno,b.fare,b.type FROM FIRST a
INNER JOIN
SECOND b ON a.rl_no = b.rollno) x, FIRST y
WHERE x.rollno = y.rl_no AND x.fare >= y.fees AND x.type IS NOT NULL GROUP BY x.rollno,x.ID ;
But this is throwing in exceptions.
ORA-00979: not a GROUP BY expression
00979. 00000 - "not a GROUP BY expression"
The expected output will be like this:
id,rollno,adm_date,fare,type
1,123456,14-11-10,1620,bs
So could someone care to show an oracle newbie what i'm doing wrong here?

It looks like there's a couple different problems here;
Firstly, you're trying to group by an x.ID column which doesn't exist; it looks like you'll want to add ID to the selected columns in your sub-query.
Secondly, when aggregating with GROUP BY, all selected columns need to be either listed in the GROUP BY statement or aggregated. If you're grouping by rollno and ID, what do you want to have happen to all the extra values for adm_date, fees, and type? Are those always going to be the same for each distinct rollno and ID pair?
If so, simply add them to the GROUP BY statement, ie,
GROUP BY adm_date, fees, type, rollno, ID
If not, you'll need to work out exactly how you want to select which one to be output; If you've got output like your example (adding in an ID column here)
ID,adm_date,fees,rollno,fare,type
1,14-11-10,100,123456,20,bs
1,10-11-12,100,123456,900,bs
1,14-11-17,100,123456,700,bs
Call that result set 'a'. If I run;
SELECT a.ID, a.rollno, SUM(a.fare) as total_fare
FROM a
GROUP BY a.ID, a.rollno
Then the result will be a single row;
ID,rollno,total_fare
1,123456,1620
So, if you also select the adm_date, fees, and type columns, oracle has no idea what you mean to do with them. You're not using them for grouping, and you're not telling oracle how you want to pick which one to use.
You could do something like
SELECT a.ID,
FIRST(a.adm_date) as first_adm_date,
FIRST(a.fees) as first_fees,
a.rollno,
SUM(a.fare) as total_fare,
FIRST(a.type) as first_type
FROM a
GROUP BY a.ID, a.rollno
Which would give the result;
ID,first_adm_date,first_fees,rollno,total_fare,first_type
1,14-11-10,100,123456,1620,bs
I'm not sure if that's what you mean to do though.

Related

Use postgresql query results to form another query

I am trying to select from one table using the select result from another table. I can run this in two queries but would like to optimize it into just one.
First query.. Select ids where matching other id
select id from lookuptable where paid = '547'
This results in something like this
6316352
6316353
6318409
6318410
6320468
6320469
6320470
6322526
6322527
6324586
6324587
6326648
I would like to then use this result to make another selection. I can do it manually like below. Note, there could be many rows with these values so I've been using a IN statement
select * from "othertable" where id in (6316352,6316353,6318409,6318410,6320468,6320469,6320470,6322526,6322527,6324586,6324587,6326648);
select
ot.*
from
"othertable" as ot
join
lookuptable as lt
on
ot.id = lt.id
where
lt.paid = '547'
The IN operator supports not just value lists but also subqueries, so you can literally write
select * from "othertable" where id in (select id from lookuptable where paid = '547');

Selecting max value grouped by specific column

Focused DB tables:
Task:
For given location ID and culture ID, get max(crop_yield.value) * culture_price.price (let's call this multiplication monetaryGain) grouped by year, so something like:
[
{
"year":2014,
"monetaryGain":...
},
{
"year":2015,
"monetaryGain":...
},
{
"year":2016,
"monetaryGain":...
},
...
]
Attempt:
SELECT cp.price * max(cy.value) AS monetaryGain, EXTRACT(YEAR FROM cy.date) AS year
FROM culture_price AS cp
JOIN culture AS c ON cp.id_culture = c.id
JOIN crop_yield AS cy ON cy.id_culture = c.id
WHERE c.id = :cultureId AND cy.id_location = :locationId AND cp.year = year
GROUP BY year
ORDER BY year
The problem:
"columns "cp.price", "cy.value" and "cy.date" must appear in the GROUP BY clause or be used in an aggregate function"
If I put these three columns in GROUP BY, I won't get expected result - It won't be grouped just by year obviously.
Does anyone have an idea on how to fix/write this query better in order to get task result?
Thanks in advance!
The fix
Rewrite monetaryGain to be:
max(cp.price * cy.value) AS monetaryGain
That way you will not be required to group by cp.price because it is not outputted as an group member, but used in aggregate.
Why?
When you write GROUP BY query you can output only columns that are in GROUP BY list and aggregate function values. Well this is expected - you expect single row per group, but you may have several distinct values for the field that is not in grouping column list.
For the same reason you can not use a non grouping column(-s) in arithmetic or any other (not aggregate) function because this would lead in several results for in single row - there would not be a way to display.
This is VERY loose explanation but I hope will help to grasp the concept.
Aliases in GROUP BY
Also you should not use aliases in GROUP BY. Use:
GROUP BY EXTRACT(YEAR FROM cy.date)
Using alias in GROUP BY is not allowed. This link might explain why: https://www.postgresql.org/message-id/7608.1259177709%40sss.pgh.pa.us

it is possible to concatenate one result set onto another in a single query?

I have a table of Verticals which have names, except one of them is called 'Other'. My task is to return a list of all Verticals, sorted in alpha order, except with 'Other' at the end. I have done it with two queries, like this:
String sqlMost = "SELECT * from core.verticals WHERE name != 'Other' order by name";
String sqlOther = "SELECT * from core.verticals WHERE name = 'Other'";
and then appended the second result in my code. Is there a way to do this in a single query, without modifying the table? I tried using UNION
(select * from core.verticals where name != 'Other' order by name)
UNION (select * from core.verticals where name = 'Other');
but the result was not ordered at all. I don't think the second query is going to hurt my execution time all that much, but I'm kind of curious if nothing else.
UNION ALL is the usual way to request a simple concatenation; without ALL an implicit DISTINCT is applied to the combined results, which often causes a sort. However, UNION ALL isn't required to preserve the order of the individual sub-results as a simple concatenation would; you'd need to ORDER the overall UNION ALL expression to lock down the order.
Another option would be to compute an integer order-override column like CASE WHEN name = 'Other' THEN 2 ELSE 1 END, and ORDER BY that column followed by name, avoiding the UNION entirely.

How to use GROUP BY with Firebird?

I'm trying create a SELECT with GROUP BY in Firebird but I can't have any success. How could I do this ?
Exception
Can't format message 13:896 -- message file C:\firebird.msg not found.
Dynamic SQL Error.
SQL error code = -104.
Invalid expression in the select list (not contained in either an aggregate function or the GROUP BY clause).
(49,765 sec)
trying
SELECT FA_DATA, FA_CODALUNO, FA_MATERIA, FA_TURMA, FA_QTDFALTA,
ALU_CODIGO, ALU_NOME,
M_CODIGO, M_DESCRICAO,
FT_CODIGO, FT_ANOLETIVO, FT_TURMA
FROM FALTAS Falta
INNER JOIN ALUNOS Aluno ON (Falta.FA_CODALUNO = Aluno.ALU_CODIGO)
INNER JOIN MATERIAS Materia ON (Falta.FA_MATERIA = Materia.M_CODIGO)
INNER JOIN FORMACAOTURMAS Turma ON (Falta.FA_TURMA = Turma.FT_CODIGO)
WHERE (Falta.FA_CODALUNO = 238) AND (Turma.FT_ANOLETIVO = 2015)
GROUP BY Materia.M_CODIGO
Simple use of group by in firebird,group by all columns
select * from T1 t
where t.id in
(SELECT t.id FROM T1 t
INNER JOIN T2 j ON j.id = t.jid
WHERE t.id = 1
GROUP BY t.id)
Using GROUP BY doesn't make sense in your example code. It is only useful when using aggregate functions (+ some other minor uses). In any case, Firebird requires you to specify all columns from the SELECT column list except those with aggregate functions in the GROUP BY clause.
Note that this is more restrictive than the SQL standard, which allows you to leave out functionally dependent columns (ie if you specify a primary key or unique key, you don't need to specify the other columns of that table).
You don't specify why you want to group (because it doesn't make much sense to do it with this query). Maybe instead you want to ORDER BY, or you want the first row for each M_CODIGO.

Specifice order to tables in postgres

I just created a temporary table as:
create temporary table userAndProductSales as
select p.p_name, u.u_name, u.s_price, u.quantity
from product p
join userAndStates u
on p.s_id = u.s_id
Now I want to select some columns with a particular order. For example, I want the select to give me an output of:
u_name1 p_name1
u_name1 p_name2
u_name1 p_name3
u_name1 p_name4
...
u_name2 p_name1
u_name2 p_name2
u_name2 p_name3
....
and so on and so forth. How do I get this ouput? I've tried something on the lines of:
select (select u_name from userandproductsales order by u_name), p_name from userandproductsales
but I'm getting an error
UPDATE: Figured out that the table I'm joining isn't giving me the correct data I want. Thanks for the help though.
Here is how to use ORDER BY :
SELECT * from userandstatesales
order by u_name , p_name
Unless there is a reason for creating a temporary table (like needing to access it later in the same session), you should avoid the expense and simply do a order by from your select. For example:
select p.p_name, u.u_name, u.s_price, u.quantity
from product p
join userAndStates u
on p.s_id = u.s_id
order by u.u_name, p.p_name;