This is what I have
select avg(visit_count) from ( SELECT count(user_id) as visit_count from table )group by user_id;
But I get the below error
ERROR 1248 (42000): Every derived table must have its own alias
if I add alias
then I get avg for only one user_id
What I want is the avg of visit_count for all user ids
SEE the picture for reference
Example 3,2.5,1.5
It means that your subquery needs to have an alias.
Like this:
select avg(visit_count) from (
select count(user_id) as visit_count from table
group by user_id) a
Your subquery is missing an alias. I think this is the version you want:
SELECT AVG(visit_count)
FROM
(
SELECT COUNT(user_id) AS visit_count
FROM yourTable
GROUP BY user_id
) t;
Note that GROUP BY belongs inside the subquery, as you want to find counts for all users.
Related
Running something like this:
SELECT user_id, username FROM `table` GROUP BY user_id HAVING COUNT(user_id) = 1
But BQ console complains that username is neither grouped nor aggregated. I'm looking at this post that explains how to remove rows that appears more than once. I'm assuming this error message is because there's no primary key or uniques in BQ? How can I get around this? I just want to eliminate repeated rows by user_id.
I just want to eliminate repeated rows by user_id.
below should do
SELECT user_id, ANY_VALUE(username) as username
FROM `table`
GROUP BY user_id
If you want one row per user_id, you can just use an aggregation function such as:
SELECT user_id, MAX(username) as username
FROM `table`
GROUP BY user_id
HAVING COUNT(user_id) = 1;
However, I might suggest using QUALIFY instead:
select t.*
from table t
where 1=1
qualify count(*) over (partition by user_id) = 1;
In hive, I want to select the records with users>=40. My table column consist of field userid. So i used
select title,sum(rating),count(userid) from table_name where count(userid)>=40
group by title order by rating desc
But it showed error like you can't use count in where clause. Also i have tried using alias like
select title,sum(rating) as ratings,count(userid) as users where users>=40 group by title order by ratings desc
Here also i struck up with error showing users is not a column name in table.
I need to get title with maximum ratings having minimum 40 users
You want the having clause:
select title, sum(rating), count(userid)
rom table_name
group by title
having count(userid) >= 40
order by sum(rating) desc;
In Hive, you may need to use a column alias, though:
select title, sum(rating) as rating, count(userid) as cnt
rom table_name
group by title
having cnt >= 40
order by rating desc;
I want to resolve below issue but not able to figure out how I can do that.
You can use the distinct keyword to get the number of different values in a count expression:
SELECT sensor_id, COUNT(DISTINCT event_type) types
FROM events
GROUP BY sensor_id
ORDER BY sensor_id ASC
I have simple table.
I need to build a SQL query and in result get the count of record where user re-played same game. So in this case we will have 3 in result..
You want a count group by
select user_id, count(*)
from your_table
group by user_id ;
You'll want to group by user_id and ensure the game count is greater than 1.
Assuming you're using SQL Server, please try something like:
SELECT user_id, count(*) as GamesPlayed
FROM table_name
GROUP BY user_id
HAVING count(*) > 1;
Looking for sql to get distinct names and count of those names from a sql table:
Structure:
id
name
other details
Do I use distinct to get each group and then count through those to get:
name1 count(name1)
name2 count(name2)
etc
Thanks
Rob.
When you want a COUNT() or a SUM(), you're using an AGGREGATE FUNCTION based on a GROUP BY clause.
As GROUP BY brings together all records with the same values specified in the GROUP BY columns, you're already getting the same effect as DISTINCT.
Except that DISTINCT doesn't allow aggregates, and GROUP BY does.
SELECT
name,
COUNT(*) AS count_of_name
FROM
yourTable
GROUP BY
name
Try :
SELECT *, COUNT(*) FROM my_table GROUP BY name
Something like this?
select name,COUNT(name) FROM Persons GROUP BY name
In the end I used:
SELECT DISTINCT `school`,COUNT(`school`) AS cat_num FROM table GROUP BY school order by cat_num DESC