In a MySQL database To get the SUM of a column I just do:
SELECT SUM(orderamount_total) FROM io__order_infos_hext
Is it possible in only one SQL request to get the SUM of orderamount_total of the different curriences defined in the column currency?
You just need a group by
SELECT currency, SUM(orderamount_total)
FROM io__order_infos_hext
group by currency
Yes It's possible. Please use the GROUP BY select clause.
SELECT SUM(orderamount_total) FROM io__order_infos_hext GROUP BY your_currency_column;
Related
I'm trying to make an SQL query, that returns all the unique names and a sum of occurences for each name.
This is what I came up with, but it merely gets the sum of all names and not the sum of each name separately.
select distinct(etunimi) as etunimi,
(select count(distinct(etunimi)) as määrä from jasenet)
from jasenet;
Is this the right way to go when solving this problem or is there another way of achieving this? thank you.
If you group by a column then aggregate functions like count() apply to each group and not the complete result set.
select etunimi, count(*)
from jasenet
group by etunimi
That because you haven't reference the colomn from outerquery with subquery
So, it should be referenced like that :
select distinct etunimi,
(select count(*)
from jasenet j1
where j1.etunimi = j.etunimi
) as määrä
from jasenet j;
However, i would also suggest to use GROUP BY clause which is more efficient than correlated subquery.
I have been trying but it seems I am missing something. I want to combine two results from two tables by a common field.
I would like to group results from these two queries by customer field.
SELECT errors.customer, count(errors.customer) as err_count,severity from errors group by customer,severity;
SELECT customer,sum(size) as Tot_size,count(customer) as Policy_count from backup group by customer;
I have tried this.
SELECT errors.customer, count(errors.customer) as err_count,severity from errors group by customer,severity union all SELECT customer,count(customer) as Policy_count ,sum(size) as Tot_size from backup group by customer;
But for some reason some columns are missing.
You should follow the requirements for union:
The UNION operator is used to combine the result-set of two or more SELECT statements.
Each SELECT statement within UNION must have the same number of columns
The columns must also have similar data types
The columns in each SELECT statement must also be in the same order
Apparently, the above items are not satisfied in your query.
Try something like this:
SELECT q1.customer, Tot_size, Policy_count, err_count, severity
FROM ( SELECT customer, SUM(size) AS Tot_size, COUNT(customer) AS Policy_count
FROM backup GROUP BY customer ) q1
LEFT JOIN ( SELECT customer, COUNT(customer) AS err_count, severity
FROM errors GROUP BY customer, severity ) q2 ON q1.costumer = q2.costumer
Your first query contains three columns and your second one contains two columns.
In order to use the UNION operator your two queries need to have the same amount of columns, and the columns should be compatible.
In your case the second query lacks a third column. If there is no corresponding column to use you can set a default such as
"'n/a' as severity "
if it should be textual or
"0 as severity "
for a numerical value.
Cheers Martin
in the below image I'm using
SELECT DISTINCT(name),date,reporting,leaving from attendance where date='2016-09-01
and I'm still getting repeating names. Why?
When using DISCTINCT, MySQL uses all columns as grouping factor. If you want group by only one column and get all corresponding column values, use GROUP BY instead
SELECT name, date, reporting, leaving FROM attendance GROUP BY name WHERE ...
Actually your all rows have distinct data apart from Name column if you want only distinct names then you can get it with help of Aggregate functions, you can use MIN or MAX as per your business requirement
SELECT Name,MAX(date),MAX(reporting),MAX(leaving)
FROM attendance
WHERE date='2016-09-01'
GROUP BY Name
I have a database that has the following columns:
-------------------
id|domain|hit_count
-------------------
And I would like to perform this query on it:
SELECT id,MIN(hit_count)
FROM table WHERE domain='$domain'
GROUP BY domain ORDER BY MIN(hit_count)
I would like this query to give me the id of the row that had the smallest hit_count for $domain. The only problem is that if I have two rows that have the same domain, say www.bestbuy.com, the query will just group by whichever one came first, and then although I will get the correct lowest hit_count, the id may or may not be the id of the row that has the lowest hit_count.
Does anyone know of a way for me to perform this query and to get the id that matches up with MIN(hit_count)? Thanks!
Try this:
SELECT id,MIN(hit_count),domain FROM table GROUP BY domain HAVING domain='$domain'
See, when you're using aggregates, either via aggregate functions (and min() is such a function) or via GROUP BY or HAVING operators, your data is being grouped. In your case it is grouped by domain. You have 2 fields in your select list, id and min(hit_count).
Now, for each group database knows which hit_count to pick, as you've specified this explicitly via the aggregate function. But what about id — which one should be included?
MySQL internally wraps such fields into max() aggregate function, which I find an error prone approach. In all other RDBMSes you will get an error for such a query.
The rule is: if you use aggregates, then all columns should be either arguments of aggregate functions or arguments of GROUP BY operator.
To achieve the desired result, you need a subquery:
SELECT id, domain, hit_count
FROM `table`
WHERE domain = '$domain'
AND hit_count = (SELECT min(hit_count) FROM `table` WHERE domain = '$domain');
I've used backticks, as table is a reserved word in SQL.
SELECT
id,
hit_count
FROM
table
WHERE
domain='$domain'
AND hit_count = (SELECT MIN(hit_count) FROM table WHERE domain='$domain')
Try this:
SELECT id,hit_count
FROM table WHERE domain='$domain'
GROUP BY domain ORDER BY hit_count ASC;
This should also work:
select id, MIN(hit_count) from table where domain="$domain";
I had same question. Please see that question below.
min(column) is not returning me correct data of other columns
You are using a GROPU BY. Which means each row in result represents a group of values.
One of those values is the group name (the value of the field you grouped by). The rest are arbitrary values from within that group.
For example the following table:
F1 | F2
1 aa
1 bb
1 cc
2 gg
2 hh
If u will group by F1: SELECT F1,F2 from T GROUP BY F1
You will get two rows:
1 and one value from (aa,bb,cc)
2 and one value from (gg,hh)
If u want a deterministic result set, you need to tell the software what algorithem to apply to the group. Several for example:
MIN
MAX
COUNT
SUM
etc etc
There is a most simplist way your query is OK just modify it with DESC keyword after GROUP BY domain
SELECT
id,
MIN(hit_count)
FROM table
WHERE domain = '$domain'
GROUP BY domain DESC
ORDER BY MIN(hit_count)
Explanation:
When you use group by with aggregate function it always selects the first record but if you restrict it with desc keyword it will select the lowest or last record of that group.
For testing puspose use this query that has only group_concat added.
SELECT
group_concat(id),
MIN(hit_count)
FROM table
WHERE domain = '$domain'
GROUP BY domain DESC
ORDER BY MIN(hit_count)
If you can have duplicated domains group by id:
SELECT id,MIN(hit_count)
FROM domain WHERE domain='$domain'
GROUP BY id ORDER BY MIN(hit_count)
hypothetic tables
user_id | hits
Can I get MySQL to return the total hits of a Select query? I know i could add them together with php or similar, just wondering if there is a pure MySQL way?
Total hits per user
SELECT userId, Sum(Hits)
FROM Table
GROUP by userId
OR
Total hits
SELECT Sum(Hits)
FROM Table
select sum(hits) from ...
Depending on the specific SQL query you're using you could either SUM a column or potentially use the 'WITH ROLLUP' GROUP modifier if you require a query-wide total.