aggregate-functions

I have a DataFrame of two columns, ID of type Int and Vec of type Vector ( org.apache.spark.mllib.linalg.Vector ). The DataFrame looks like follow: ID,Vec 1,[0,0,5] 1,[4,0,1] 1,[1,2,1] 2,[7,5,0] 2,[3,3,4] 3,[0,8,1] 3,[0,0,1] 3,[7,7,7] .... I would like to do a groupBy($"ID") then apply an aggregation on the rows inside each group by summing the vectors. The desired output of the above example would be: ID,SumOfVectors 1,[5,2,7] 2,[10,8,4] 3,[7,15,9] ... The available aggregation functions will not work, e.g. df.groupBy($"ID").agg(sum($"Vec") will lead to an ClassCastException. How to implement

This question already has an answer here: Multiple aggregations of the same column using pandas GroupBy.agg() 3 answers I'm having trouble with Pandas' groupby functionality. I've read the documentation , but I can't see to figure out how to apply aggregate functions to multiple columns and have custom names for those columns. This comes very close, but the data structure returned has nested column headings: data.groupby("Country").agg( {"column1": {"foo": sum()}, "column2": {"mean": np.mean, "std": np.std}}) (ie. I want to take the mean and std of column2, but return those columns as "mean"

I have a working query that is grouping data by hardware model and a result, but the problem is there are many "results" . I have tried to reduce that down to "if result = 0 then keep as 0, else set it to 1" . This generally works, but I end up having: day | name | type | case | count ------------+----------------+------+------+------- 2013-11-06 | modelA | 1 | 0 | 972 2013-11-06 | modelA | 1 | 1 | 42 2013-11-06 | modelA | 1 | 1 | 2 2013-11-06 | modelA | 1 | 1 | 11 2013-11-06 | modelB | 1 | 0 | 456 2013-11-06 | modelB | 1 | 1 | 16 2013-11-06 | modelB | 1 | 1 | 8 2013-11-06 | modelB | 3 | 0 |

I've just got myself a little bit stuck with some SQL. I don't think I can phrase the question brilliantly - so let me show you. I have two tables, one called person, one called appointment. I'm trying to return the number of appointments a person has (including if they have zero). Appointment contains the person_id and there is a person_id per appointment. So COUNT(person_id) is a sensible approach. The query: SELECT person_id, COUNT(person_id) AS "number_of_appointments" FROM appointment GROUP BY person_id; Will return correctly, the number of appointments a person_id has. However, a person

currently im working with mysql 5.7 in development, and 5.6 in production. Each time i run a query with a group by in development i get some error like "Error Code: 1055. Expression #1 of SELECT list is not in GROUP BY " Here is the query. SELECT c.id, c.name, i.* FROM countries c, images i WHERE i.country_id = c.id GROUP BY c.id; Fixed for 5.7; SELECT c.id, c.name, ANY_VALUE(i.url) url, ANY_VALUE(i.lat) lat, ANY_VALUE(i.lng) lng FROM countries c, images i WHERE i.country_id = c.id GROUP BY c.id; For solving that I use the mysql function from 5.7 ANY_VALUE, but the main issue is that its not