Count the number of registered players per month :: Playing with Projections — All the relevant information for the workshop.

Count the number of registered players per month

This challenge builds on top of the previous one. You should be able to group player registrations per month. The expected output looks like this:

2019-8: 15
2019-9: 42

Tip

The events are ordered on time, so you should not do any ordering yourself.

Answer

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Basic

2019-8: 29
2019-9: 24

Full

2018-5: 17
2018-6: 43
2018-7: 49
2018-8: 58
2018-9: 123
2018-10: 115
2018-11: 146
2018-12: 176
2019-1: 134
2019-2: 95
2019-3: 91
2019-4: 58
2019-5: 110
2019-6: 121
2019-7: 118
2019-8: 73

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