Oracle - SQL developer query using count - oracle

I have this table called, ACTIVITIES:
Name Activity Minutes
JOSE videogames 50
MARISSA videogames 50
TINA CHESS 90
JAKE CHESS 95
For each activity in the table, how do I make a count of how many persons did that activity? I would like to print the activity, the count, and the sum of the minutes in my query.
I tried working by parts & this was my attempt:
SELECT Distinct(Activity), count(Activity) as Total
FROM ACTIVITIES;
However, the query result gave me an error saying: "not a single-group group function"

You can use a group by clause to first group the table by activity then do the count and the sum. For example:
SELECT count(*), sum(NUMOFMINUTES), Activity
FROM activities
GROUP BY activity

Use group by to get the count/sum per activity like so:
select activity, count (activity) as totalcount, sum(minutes) as totalminutes
from activities
group by activity
If you want to get some aggregate value such as a count of a specific value, you first need to group the data into subsets based on the distinct values of that column. That is what that error message was referring to. Note that when you group by activity, the records will consider and display only the distinct values of activity, so you won't need to use the distinct keyword.

TRY this
SELECT DISTINCT(Activity),COUNT(Activity) AS Total FROM ACTIVITIES
GROUP BY Activity

Whenever you use any agreegate function and retrieves another field with it on which you are not performing agreegation then you have to use group by clause with non-agreegate field. so add 'group by Activity' at the end of your query.

Related

Oracle Sql group function is not allowed here

I need someone who can explain me about "group function is not allowed here" because I don't understand it and I would like to understand it.
I have to get the product name and the unit price of the products that have a price above the average
I initially tried to use this, but oracle quickly told me that it was wrong.
SELECT productname,unitprice
FROM products
WHERE unitprice>(AVG(unitprice));
search for information and found that I could get it this way:
SELECT productname,unitprice FROM products
WHERE unitprice > (SELECT AVG(unitprice) FROM products);
What I want to know is why do you put two select?
What does group function is not allowed here mean?
More than once I have encountered this error and I would like to be able to understand what to do when it appears
Thank you very much for your time
The phrase "group function not allowed here" is referring to anything that is in some way an "aggregation" of data, eg SUM, MIN, MAX, etc et. These functions must operate on a set of rows, and to operate on a set of rows you need to do a SELECT statement. (I'm leaving out UPDATE/DELETE here)
If this was not the case, you would end up with ambiguities, for example, lets say we allowed this:
select *
from products
where region = 'USA'
and avg(price) > 10
Does this mean you want the average prices across all products, or just the average price for those products in the USA? The syntax is no longer deterministic.
Here's another option:
SELECT *
FROM (
SELECT productname,unitprice,AVG(unitprice) OVER (PARTITION BY 1) avg_price
FROM products)
WHERE unitprice > avg_price
The reason your original SQL doesn't work is because you didn't tell Oracle how to compute the average. What table should it find it in? What rows should it include? What, if any, grouping do you wish to apply? None of that is communicated with "WHERE unitprice>(AVG(unitprice))".
Now, as a human, I can make a pretty educated guess that you intend the averaging to happen over the same set of rows you select from the main query, with the same granularity (no grouping). We can accomplish that either by using a sub-query to make a second pass on the table, as your second SQL did, or the newer windowing capabilities of aggregate functions to internally make a second pass on your query block results, as I did in my answer. Using the OVER clause, you can tell Oracle exactly what rows to include (ROWS BETWEEN ...) and how to group it (PARTITION BY...).

Oracle duplicate field but still correct

So i built a query for my leadership team that was correct, but i dont understand why oracle gave me the correct answer.
i have 3 tables that i needed to get data out of in order to get the total billed amount.
Here is my query (please forgive me, my 2nd post and im not sure how to properly format my querys)
select b.total_amount_billed as billed from t1.billing_information b
where b.billing_no in
(select h.billing_no
from t1.res_history h where h.res_seq_no in
(Select r.reservation_seq_no
from t1.res r where r.customer_order_no in ('THO40000') ))
so in the deepest select, i take the the sequence number where my customer order number was THO40000, this query returns 2 sequence numbers.
the second sub query returns the billing numbers for my order from the history table where the sequence number match, in this case for this order they both use the same billing number, 312000.
the final select, returns my total billed amount where it matched my billing numbers it found, in my case $110.
the query works, but what i dont understand is why is it not duplicated? why does it not return 110, for each time it found 312000, giving me 2 records of 110? the billing number is a PK in the billing_information table. im not sure why it worked without me using the distinct keyword on the query for the billing number.
anyway thanks for the help, ill do my best to explain if you have questions!
You are being saved because you used IN to get the billing_no values to use, rather than an INNER JOIN between the two tables using b.billing_no = h.billing_no. A join would have duplicated the records, but your IN query is essentially this:
select b.total_amount_billed as billed
from t1.billing_information b
where b.billing_no in (312000, 312000);
If there is a single row in billing_information having billing_no equal to 312000, it is in the list, so the WHERE condition is true and it is included in the results. The fact that it is in the list twice doesn't make the IN condition "more true".

OBIEE Merge two queries (join)

I need help.
I am new to obiee (recently moved from business objects and re-creating all reports in obiee).
Here is an example I need help with. I have created an analysis where I am listing all orders with their target delivery dates and number of products in each order.
Order Id......Target Delivery Date...No of products
Abc....1/1/2016.....5
I want to add to a column next to No of products called "No of prods delivered on time". I want to compare delivery date of each product within a order with the target delivery date and
Give count of products delivered within the target date.. So the output should be
Abc....1/1/2016....5.....3
Where 3 is number of products delivered on time.
I could do it in BO by running two queries and merging them however in obiee I am not able to add second query to my analysis. I did try at product level using case when target date >=delivery date then 1 else 0 and wrapped this with sum function to aggregate but it didn't work ..
Appreciate your help in this. Searching for this topics give me results for running queries from multiple subject area :(
You also have unions in OBIEE, you union the results of 2 queries which return the same structure, so you have query A with Order ID, Target Date, No Products and a Dummy column with a 0 and default agregation Sum, and a second query with Order ID, Target Date, Dummy column summing 0 and the number of products delivered.
You do all this in the criteria tab of the analysis. It's important the order in which you put your columns, because that's what OBIEE is using to do the union.
Regards

Extract distinct values

I have a big table of emails which has many emails repeated. I want to extract DISTINCT emails from it. Can't do it due to unavailability of DISTINCT and limitation of GROUP EACH BY or TOP function (Errors:Resources exceeded during query execution.).
A simple query with GROUP BY (without aggregate functions) should be enough:
SELECT email
FROM YouTableWithDuplicateEMails
GROUP BY email

Compute average number of rows per group in Sql Server Reporting Services

I have a table widget in reporting services where I group rows on a given id.
For each group, I display the number of rows per group, using countrows().
How can I display the average number of rows per group at the end of my report ?
What I am missing is : how to count the number of groups?
This is from memory - not sure if this expression is correct:
= Count(Fields!ID.Value) / CountDistinct(Fields!ID.Value)
Assuming that the "ID" you're grouping by is a single field, that sort of expression should get you what you want.

Resources