total novice here with SQL SUM function question. So, SUM function itself works as I expected it to:
select ID, sum(amount)
from table1
group by ID
There are several records for each ID and my goal is to summarize each ID on one row where the next column would give me the summarized amount of column AMOUNT.
This works fine, however I also need to filter out based on certain criteria in the summarized amount field. I.e. only look for results where the summarized amount is either bigger, smaller or between certain number.
This is the part I'm struggling with, as I can't seem to use column AMOUNT, as this messes up summarizing results.
Column name for summarized results is shown as "00002", however using this in the between or > / < clause does not work either. Tried this:
select ID, sum(amount)
from table1
where 00002 > 1000
group by ID
No error message, just blank result, however plenty of summarized results with values over 1000.
Unfortunately not sure on the engine the database runs on, however it should be some IBM-based product.
The WHERE clause will filter individual rows that don't match the condition before aggregating them.
If you want to do post aggregation filtering you need to use the HAVING Clause.
HAVING will apply the filter to the results after being grouped.
select ID, sum(amount)
from table1
group by ID
having sum(amount) > 1000
Related
Q1: After using the Group By function, why does it only output one row of each group at most? Does this mean that having is supposed to filter the group rather than filter the records in each group?
Q2: I want to find the records in each group whose ages are greater than the average age of that group. I tried the following, but it returns nothing. How should I fix this?
SELECT *, avg(age) FROM Mytable Group By country Having age > avg(age)
Thanks!!!!
You can calculate the average age for each country in a subquery and join that to your table for filtering:
SELECT mt.*, MtAvg.AvgAge
FROM Mytable mt
inner join
(
select mtavgs.country
, avg(mtavgs.age) as AvgAge
from Mytable mtavgs
group by mtavgs.country
) MTAvg
on mtavg.country=mt.country
and mt.Age > mtavg.AvgAge
GROUP BY returns always 1 row per unique combination of values in the GROUP BY columns listed (provided that they are not removed by a HAVING clause). The subquery in our example (alias: MTAvg) will calculate a single row per country. We will use its results for filtering the main table rows by applying the condition in the INNER JOIN clause; we will also report that average by including the calculated average age.
GROUP BY is a keyword that is called an aggregate function. Check this out here for further reading SQL Group By tutorial
What it does is it lumps all the results together into one row. In your example it would lump all the results with the same country together.
Not quite sure what exactly your query needs to be to solve your exact problem. I would however look into what are called window functions in SQL. I believe what you first need to do is write a window function to find the average age in each group. Then you can write a query to return the results you need
Depending on your dbms type and version, you may be able to use a "window function" that will calculate the average per country and with this approach it makes the calculation available on every row. Once that data is present as a "derived table" you can simply use a where clause to filter for the ages that are greater then the calculated average per country.
SELECT mt.*
FROM (
SELECT *
, avg(age) OVER(PARTITION BY country) AS AvgAge
FROM Mytable
) mt
WHERE mt.Age > mt.AvgAge
On a report builder 3.0, i retreived some items and counted them using a Count aggregate. Now i want to order them from highest to lowest. How do i use the ORDER BY function on the aggregated column? The picture below show the a column that i want to ORDER BY it, it is ticked.
Pic
The code is vers simple as shown bellow:
SELECT DISTINCT act_id,NameOfAct,
FROM Acts
Your picture indicates you also want a Total row at the bottom:
SELECT
COALESCE(NameOfAct,'Total') NameOfAct,
COUNT(DISTINCT act_id) c
FROM Acts
GROUP BY ROLLUP(NameOfAct)
ORDER BY
CASE WHEN NameOfAct is null THEN 1 ELSE 0 END,
c DESC;
Result of example data:
NameOfAct count
-------------- -------
Act_B 3
Act_A 2
Act_Z 1
Total 6
Try it with example rows at: http://sqlfiddle.com/#!18/dbd6c/2
I looked at the Pic. So you might have duplicate acts with the same name. And you want to know the number of acts that have the same unique name.
You might want to group the results by name:
GROUP BY NameOfAct
And include the act names and their counts in the query results:
SELECT NameOfAct, COUNT(*) AS ActCount
(Since the act_id column is not included in the groups, you need to omit it in the SELECT. The DISTINCT is also not necessary anymore, since all groups are unique already.)
Finally, you can sort the data (probably descending to get the acts with the largest count on top):
ORDER BY ActCount DESC
Your complete query would become something like this:
SELECT NameOfAct, COUNT(*) AS ActCount
FROM Acts
GROUP BY NameOfAct
ORDER BY ActCount DESC
Edit:
By the way, you use field "act_id" in your SELECT clause. That's somewhat confusing. If you want to know counts, you want to look at either the complete table data or group the table data into smaller groups (with the GROUP BY clause). Then you can use aggregate functions to get more information about those groups (or the whole table), like counts, average values, minima, maxima...
Single record information, like an act's ID in your case, is typically not important if you want to use statistic/aggregate methods on grouped data. Suppose your query returns an act name which is used 10 times. Then you have 10 records in your table, each with a unique act_id, but with the same name.
If you need just one act_id that represents each group / act name (and assuming act_id is an autonumbering field), you might include the latest / largest act_id value in the query using the MAX aggregate function:
SELECT NameOfAct, COUNT(*) AS ActCount, MAX(act_id) AS LatestActId
(The rest of the query remains the same.)
Basically, I'm trying to retrieve only 1 record from a table based on catalog_no and packing_list_no. However, the table I'm retrieving the information from has additional details that I don't need but makes the 1 record I need into 3 distinct records.
I tried summing and grouping the info, but I'm still getting 3 records instead of 1.
Any ideas of how to solve this issue?
Your GROUP BY groups your result on the columns quantity picked, quantity shipped and weight shipped. A different value in any of those columns will result into a different row.
You can drop the GROUP BY clause all together, if the desirable result is the packing list and catalog no that you have specified. You can use the GROUP BY clause to columns that you do not use sum to group the result set.
SELECT catalog_no, sum(qty_picked), sum(qty_shipped), sum(weight_shipped), packing_list_no, bay_no, carrier_code, tracking_no FROM oeorder_shipping
WHERE packing_list_no='CP12618525' AND catalog_no='437656500'
GROUP BY bay_no, carrier_code, tracking_no;
I have a table with some search results. The search results maybe repeated because each result may be found using a different metric. I want to then query this table select only the distinct results using the ID column. So to summarize I have a table with an ID column but the IDs may be repeated and I want to select only one of each ID with MS Access SQL, how should I go about doing this?
Ok I have some more info after trying a couple of the suggestions. The Mins, and Maxes won't work because the column they are operating on cannot be shown. I get an error like You tried to execute a query that does not include the specified expression... I now have all my data sorted, here is what it looks like
ID|Description|searchScore
97 test 1
97 test .95
120 ball .94
97 test .8
120 ball .7
so the problem is that since the rows were put into the table using different search criteria I have duplicated rows with different scores. What I want to do is select only one of each ID sorted by the searchScore descending. Any ideas?
SELECT DISTINCT ID
FROM Search_Table;
Based on the last update to your question, the following query seems appropriate.
SELECT ID, [Description], Max(searchScore)
FROM Search_Table
GROUP BY ID, [Description];
However that's nearly the same as Gordon's suggestion from yesterday, so I'm unsure whether this is what you want.
Here is a way where you can get one of the search criteria:
select id, min(search_criteria)
from t
group by id
This will always return the first one alphabetically. You can also easily get the last one using max().
You could also use:
select id, first(search_criteria)
from t
group by id
I am running the following queries against a database:
CREATE TEMPORARY TABLE med_error_third_party_tmp
SELECT `med_error_category`.description AS category, `med_error_third_party_category`.error_count AS error_count
FROM
`med_error_category` INNER JOIN `med_error_third_party_category` ON med_error_category.`id` = `med_error_third_party_category`.`category`
WHERE
year = 2003
GROUP BY `med_error_category`.id;
The only problem is that when I create the temporary table and do a select * on it then it returns multiple rows, but the query above only returns one row. It seems to always return a single row unless I specify a GROUP BY, but then it returns a percentage of 1.0 like it should with a GROUP BY.
SELECT category,
error_count/SUM(error_count) AS percentage
FROM med_error_third_party_tmp;
Here are the server specs:
Server version: 5.0.77
Protocol version: 10
Server: Localhost via UNIX socket
Does anybody see a problem with this that is causing the problem?
Standard SQL requires you to specify a GROUP BY clause if any column is not wrapped in an aggregate function (IE: MIN, MAX, COUNT, SUM, AVG, etc), but MySQL supports "hidden columns in the GROUP BY" -- which is why:
SELECT category,
error_count/SUM(error_count) AS percentage
FROM med_error_third_party_tmp;
...runs without error. The problem with the functionality is that because there's no GROUP BY, the SUM is the SUM of the error_count column for the entire table. But the other column values are completely arbitrary - they can't be relied upon.
This:
SELECT category,
error_count/(SELECT SUM(error_count)
FROM med_error_third_party_tmp) AS percentage
FROM med_error_third_party_tmp;
...will give you a percentage on a per row basis -- category values will be duplicated because there's no grouping.
This:
SELECT category,
SUM(error_count)/x.total AS percentage
FROM med_error_third_party_tmp
JOIN (SELECT SUM(error_count) AS total
FROM med_error_third_party_tmp) x
GROUP BY category
...will gives you a percentage per category of the sum of the categories error_count values vs the sum of the error_count values for the entire table.
another way to do it - without the temp table as seperate item...
select category, error_count/sum(error_count) "Percentage"
from (SELECT mec.description category
, metpc.error_count
FROM med_error_category mec
, med_error_third_party_category metpc
WHERE mec.id = metpc.category
AND year = 2003
GROUP BY mec.id
);
i think you will notice that the percentage is unchanging over the categories. This is probably not what you want - you probably want to group the errors by category as well.