Peewee counting all objects with specific value

Question

My struggle is not with creating a table, I can create a table. The problem is to populate columns based off of calculations of other tables.

I have looked at How to create all tables defined in models using peewee and this is not helping me do summations and count etc..

I have a hypothetical database (database.db) and created these two tables:

Table 1 (from class User)

id name
1  Jamie
2  Sam
3  Mary

Table 2 (from class Sessions)

id SessionId
1  4121
1  4333
1  4333
3  5432

I simply want to create a new table using peewee:

id  name   sessionCount TopSession # <- (Session that appears most for the given user)
1   Jamie  3            4333
2   Sam    0            NaN
3   Mary   1            5432
4 ...

Each entry in Table1 and Table2 was created using User.create(...) or Sessions.create(...)

The new table should look at the data that is in the database.db (ie Table1 and Table2) and perform the calculations.

This would be simple in Pandas, but I cant seem to find a query that can do this. Please help

No, the problem I have is not with creating a table. The struggle is to get the values for ```sessionCount``` and ```TopSession``` in the desired table — Llewellyn Hattingh, Jan 30 '20 at 15:38
Please help, this is really a simple thing that I want to do, but I cant seem to find a way to do it — Llewellyn Hattingh, Jan 30 '20 at 15:44

score 0 · Answer 1 · edited Feb 02 '20 at 12:35

0

I found it...

query = Sessions.select(fn.COUNT(Sessions.id)).where(Sessions.id==1)
count = query.scalar()
print(count)
>>> 3

# Or:
query = Sessions.select().where(Sessions.id == 1).count()
3

For anyone out there : )

edited Feb 02 '20 at 12:35

coleifer

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answered Jan 30 '20 at 15:50

Llewellyn Hattingh

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Peewee counting all objects with specific value

1 Answers1