I have table with columns as id,title,relation_key. I wanted to get count(*) as well as title for correspondingrelation_key column.
My table contains the following data:
id title relation_key
55 title1111 10
56 title2222 10
57 MytitleVVV 20
58 MytitlleXXX 20
I tried:
select title,count(*) from table where relation_key=10 group by title
But its returning 1 row only. I want both records of title for relation_key=10
You probably want something along these lines:
select title, count(*) over (partition by relation_key)
from table
where relation_key = 10
The result of this would yield:
title | count
----------+------
title1111 | 2
title2222 | 2
Note that you cannot select fields that are not part of the GROUP BY clause in Oracle (as in most other databases).
As a general rule of thumb, you should avoid grouping if you don't really want to group data, but just use aggregate functions such as count(*). Most of Oracle's aggregate functions can be transformed into window functions by adding an over() clause, removing the need for a GROUP BY clause.
If you are getting an Error then Please try with following.
select title,count(*) from table where relation_key=10 group by title,relation_key
Related
I am querying a Presto table where I want to calculate what percentage of the total a certain subset of the rows account for.
Consider a table like this:
id
m
1
5
1
7
2
9
3
8
I want to query to report how much of the total measure (m) is contributed by each id. In this example, the total of the measure column is 29 can I find it with a query like...
SELECT SUM("m") FROM t;
output:
sqlite> SELECT SUM("m") FROM t;
29
Then I want to subtotal by id for some of the ids like
SELECT "id", SUM("m") AS "sub_total" FROM t WHERE "id" IN ('1','3') GROUP BY id;
output:
sqlite> SELECT "id", SUM("m") AS "sub_total" FROM t WHERE "id" IN ('1','3') GROUP BY id;
1|12
3|8
Now I want to add a third column where the subtotals are divided by the grand total (29) to get the percentage for each selected id.
I tried:
sqlite>
WITH a AS (
SELECT SUM("m") AS g FROM t )
SELECT "id", SUM("m") AS "sub_total", SUM(m)*100/"a"."g"
FROM a, t
WHERE "t"."id" IN ('1','3') GROUP BY "t"."id";
output:
1|12|41
3|8|27
Which is all good in SQLLite3! But when I translate this to my actual Presto DB (and the right tables and columns), I get this error:
presto error: line 10:5: 'a.g' must be an aggregate expression or appear in GROUP BY clause
I can't understand what I'm missing here or why this would be different in Presto.
When you have a GROUP BY in your query, all expressions that the query is returning must be either:
the expression you are grouping by
or aggregate function
For example if you do GROUP BY id, the resulting query will return one row per id - you cannot just use m, because with id = 1 there are two values: 5 and 7 - so what should be returned? First value, last, sum, average? You need to tell it using aggregate function like sum(m).
Same with a.g - you need to add it to GROUP BY.
WITH a AS (
SELECT SUM("m") AS g FROM t )
SELECT "id", SUM("m") AS "sub_total", SUM(m)*100/"a"."g"
FROM a, t
WHERE "t"."id" IN ('1','3') GROUP BY "t"."id", "a"."g";
There's nothing special about PrestoDB here, it's more SQLite that's less strict, actually most other database engines would complain about your case.
I have this query:
select id, convert(nvarchar(10), pubdate, 102) as pubdate,
channel_title, title, description, link, vertinimas
from table1
where statusid > 0
and channel_title = 'channel1'
group by title
order by pubdate desc
to exclude duplicate entries in the field "title" i added group by title in the end, but an error occurs:
"is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause."
GROUP BY clause can only be used with aggregate functions like count(), min(), max(), sum() etc. The select query can only select the columns which are part of GROUP BY clause or on which you are applying an aggregate function.
For example you have a STUDENT table like below:
ID
NAME
SUBJECT
MARKS
1
FOO
ENGLISH
80
2
FOO
MATH
70
3
BAR
ENGLISH
100
4
BAR
MATH
50
5
ZIL
ENGLISH
90
6
ZIL
MATH
75
you can write a query like:
SELECT NAME, SUM(MARKS) AS TOTAL FROM STUDENT GROUP BY NAME;
Hear in the above query NAME is part of your GROUP BY clause and we are applying sum() aggregate function on column on MARKS. This will give us a result like below:
NAME
MARKS
FOO
150
BAR
150
ZIL
165
In your query above in the post, only title is part of GROUP BY column. Rest all the column like id, pubdate, channel_title, title, description, link, vertinimas, they are neither part of GROUP BY clause nor passed as a parameter in any aggregate function.
If you want to find / exclude / delete duplicate rows, you can checkout this blog post. This guy has explained it pretty well. Here is the like to find and delete duplicate records!
This is how my query results look like currently. How can I get the MAX() value for each unique id ?
IE,
for 5267139 is 8.
for 5267145 is 4
5267136 5
5267137 8
5267137 2
5267139 8
5267139 5
5267139 3
5267141 4
5267141 3
5267145 4
5267145 3
5267146 1
5267147 2
5267152 3
5267153 3
5267155 8
SELECT DISTINCT st.ScoreID, st.ScoreTrackingTypeID
FROM ScoreTrackingType stt
LEFT JOIN ScoreTracking st
ON stt.ScoreTrackingTypeID = st.ScoreTrackingTypeID
ORDER BY st.ScoreID, st.ScoreTrackingTypeID DESC
GROUP BY will partition your table into separate blocks based on the column(s) you specify. You can then apply an aggregate function (MAX in this case) against each of the blocks -- this behavior applies by default with the below syntax:
SELECT First_column, MAX(Second_column) AS Max_second_column
FROM Table
GROUP BY First_column
EDIT: Based on the query above, it looks like you don't really need the ScoreTrackingType table at all, but leaving it in place, you could use:
SELECT st.ScoreID, MAX(st.ScoreTrackingTypeID) AS ScoreTrackingTypeID
FROM ScoreTrackingType stt
LEFT JOIN ScoreTracking st ON stt.ScoreTrackingTypeID = st.ScoreTrackingTypeID
GROUP BY st.ScoreID
ORDER BY st.ScoreID
The GROUP BY will obviate the need for DISTINCT, MAX will give you the value you are looking for, and the ORDER BY will still apply, but since there will only be a single ScoreTrackingTypeID value for each ScoreID you can pull it out of the ordering.
I'm trying to add a column which calculates percentages of different products in MS Access Query. Basically, this is the structure of the query that I'm trying to reach:
Product |
Total |
Percentage
Prod1 |
15 |
21.13%
Prod2 |
23 |
32.39%
Prod3 |
33 |
46.48%
Product |
71 |
100%
The formula for finding the percent I use is: ([Total Q of a Product]/[Totals of all Products])*100, but when I try to use the expression builder (since my SQL skills are basic) in MS Access to calculate it..
= [CountOfProcuts] / Sum([CountOfProducts])
..I receive an error message "Cannot have aggregate function in GROUP BY clause.. (and the expression goes here)". I also tried the option with two queries: one that calculates only the totals and another that use the first one to calculate the percentages, but the result was the same.
I'll be grateful if someone can help me with this.
You can get all but the last row of your desired output with this query.
SELECT
y.Product,
y.Total,
Format((y.Total/sub.SumOfTotal),'#.##%') AS Percentage
FROM
YourTable AS y,
(
SELECT Sum(Total) AS SumOfTotal
FROM YourTable
) AS sub;
Since that query does not include a JOIN or WHERE condition, it returns a cross join between the table and the single row of the subquery.
If you need the last row from your question example, you can UNION the query with another which returns the fabricated row you want. In this example, I used a custom Dual table which is designed to always contain one and only one row. But you could substitute another table or query which returns a single row.
SELECT
y.Product,
y.Total,
Format((y.Total/sub.SumOfTotal),'#.##%') AS Percentage
FROM
YourTable AS y,
(
SELECT Sum(Total) AS SumOfTotal
FROM YourTable
) AS sub
UNION ALL
SELECT
'Product',
DSum('Total', 'YourTable'),
'100%'
FROM Dual;
Hi I know how to use the group by clause for sql. I am not sure how to explain this so Ill draw some charts. Here is my original data:
Name Location
----------------------
user1 1
user1 9
user1 3
user2 1
user2 10
user3 97
Here is the output I need
Name Location
----------------------
user1 1
9
3
user2 1
10
user3 97
Is this even possible?
The normal method for this is to handle it in the presentation layer, not the database layer.
Reasons:
The Name field is a property of that data row
If you leave the Name out, how do you know what Location goes with which name?
You are implicitly relying on the order of the data, which in SQL is a very bad practice (since there is no inherent ordering to the returned data)
Any solution will need to involve a cursor or a loop, which is not what SQL is optimized for - it likes working in SETS not on individual rows
Hope this helps
SELECT A.FINAL_NAME, A.LOCATION
FROM (SELECT DISTINCT DECODE((LAG(YT.NAME, 1) OVER(ORDER BY YT.NAME)),
YT.NAME,
NULL,
YT.NAME) AS FINAL_NAME,
YT.NAME,
YT.LOCATION
FROM YOUR_TABLE_7 YT) A
As Jirka correctly pointed out, I was using the Outer select, distinct and raw Name unnecessarily. My mistake was that as I used DISTINCT , I got the resulted sorted like
1 1
2 user2 1
3 user3 97
4 user1 1
5 3
6 9
7 10
I wanted to avoid output like this.
Hence I added the raw id and outer select
However , removing the DISTINCT solves the problem.
Hence only this much is enough
SELECT DECODE((LAG(YT.NAME, 1) OVER(ORDER BY YT.NAME)),
YT.NAME,
NULL,
YT.NAME) AS FINAL_NAME,
YT.LOCATION
FROM SO_BUFFER_TABLE_7 YT
Thanks Jirka
If you're using straight SQL*Plus to make your report (don't laugh, you can do some pretty cool stuff with it), you can do this with the BREAK command:
SQL> break on name
SQL> WITH q AS (
SELECT 'user1' NAME, 1 LOCATION FROM dual
UNION ALL
SELECT 'user1', 9 FROM dual
UNION ALL
SELECT 'user1', 3 FROM dual
UNION ALL
SELECT 'user2', 1 FROM dual
UNION ALL
SELECT 'user2', 10 FROM dual
UNION ALL
SELECT 'user3', 97 FROM dual
)
SELECT NAME,LOCATION
FROM q
ORDER BY name;
NAME LOCATION
----- ----------
user1 1
9
3
user2 1
10
user3 97
6 rows selected.
SQL>
I cannot but agree with the other commenters that this kind of problem does not look like it should ever be solved using SQL, but let us face it anyway.
SELECT
CASE main.name WHERE preceding_id IS NULL THEN main.name ELSE null END,
main.location
FROM mytable main LEFT JOIN mytable preceding
ON main.name = preceding.name AND MIN(preceding.id) < main.id
GROUP BY main.id, main.name, main.location, preceding.name
ORDER BY main.id
The GROUP BY clause is not responsible for the grouping job, at least not directly. In the first approximation, an outer join to the same table (LEFT JOIN below) can be used to determine on which row a particular value occurs for the first time. This is what we are after. This assumes that there are some unique id values that make it possible to arbitrarily order all the records. (The ORDER BY clause does NOT do this; it orders the output, not the input of the whole computation, but it is still necessary to make sure that the output is presented correctly, because the remaining SQL does not imply any particular order of processing.)
As you can see, there is still a GROUP BY clause in the SQL, but with a perhaps unexpected purpose. Its job is to "undo" a side effect of the LEFT JOIN, which is duplication of all main records that have many "preceding" ( = successfully joined) records.
This is quite normal with GROUP BY. The typical effect of a GROUP BY clause is a reduction of the number of records; and impossibility to query or test columns NOT listed in the GROUP BY clause, except through aggregate functions like COUNT, MIN, MAX, or SUM. This is because these columns really represent "groups of values" due to the GROUP BY, not just specific values.
If you are using SQL*Plus, use the BREAK function. In this case, break on NAME.
If you are using another reporting tool, you may be able to compare the "name" field to the previous record and suppress printing when they are equal.
If you use GROUP BY, output rows are sorted according to the GROUP BY columns as if you had an ORDER BY for the same columns. To avoid the overhead of sorting that GROUP BY produces, add ORDER BY NULL:
SELECT a, COUNT(b) FROM test_table GROUP BY a ORDER BY NULL;
Relying on implicit GROUP BY sorting in MySQL 5.6 is deprecated. To achieve a specific sort order of grouped results, it is preferable to use an explicit ORDER BY clause. GROUP BY sorting is a MySQL extension that may change in a future release; for example, to make it possible for the optimizer to order groupings in whatever manner it deems most efficient and to avoid the sorting overhead.
For full information - http://academy.comingweek.com/sql-groupby-clause/
SQL GROUP BY STATEMENT
SQL GROUP BY clause is used in collaboration with the SELECT statement to arrange identical data into groups.
Syntax:
1. SELECT column_nm, aggregate_function(column_nm) FROM table_nm WHERE column_nm operator value GROUP BY column_nm;
Example :
To understand the GROUP BY clauserefer the sample database.Below table showing fields from “order” table:
1. |EMPORD_ID|employee1ID|customerID|shippers_ID|
Below table showing fields from “shipper” table:
1. | shippers_ID| shippers_Name |
Below table showing fields from “table_emp1” table:
1. | employee1ID| first1_nm | last1_nm |
Example :
To find the number of orders sent by each shipper.
1. SELECT shipper.shippers_Name, COUNT (orders.EMPORD_ID) AS No_of_orders FROM orders LEFT JOIN shipper ON orders.shippers_ID = shipper.shippers_ID GROUP BY shippers_Name;
1. | shippers_Name | No_of_orders |
Example :
To use GROUP BY statement on more than one column.
1. SELECT shipper.shippers_Name, table_emp1.last1_nm, COUNT (orders.EMPORD_ID) AS No_of_orders FROM ((orders INNER JOIN shipper ON orders.shippers_ID=shipper.shippers_ID) INNER JOIN table_emp1 ON orders.employee1ID = table_emp1.employee1ID)
2. GROUP BY shippers_Name,last1_nm;
| shippers_Name | last1_nm |No_of_orders |
for more clarification refer my link
http://academy.comingweek.com/sql-groupby-clause/