Beginner needing help

[Michael Turnbull]

Hi all, I'm new to this forum and just starting out on my SQL learnings in Google's Big Query. 

I have an issue where I'm trying to show data in a particular way based on multiple events. I'll try my best to explain my problem, and hopefully someone can help or offer advice. Thanks in advance. 

Problem statement - 

I'm trying to show when a customer (who has a unique identifier) has a series of job references booked over a period of 3 weeks, in order to show volume of repeat jobs for that customer. 

Example of what I have (trying to layout how I have the data in rows and columns)

Row 1 - (Column 1) = Week 1, (Column 2) = Customer 123, (Column 3) = Job ref 123

Row 2 - (Column 1) = Week 3, (Column 2) = Customer 123, (Column 3) = Job ref 345

I'd like to be able to simplify this view and show that over a 3 week period, that Customer 123 has had a repeat job ref against their unique customer number. 

I'd like it to almost show something like the below 

Row 1 - (Column 1) = Week of initial job, (Column 2) = Customer 123, Column 3 = count of first job in week 1, (Column 4) = Count of any repeat jobs in the weeks after week 1 occurred. 

Hopefully that makes sense, and this is my first time posting, so any further info needed then please ask. 

Thanks in advance for any help relating to my issue. 

[wokmou]

Aggregate Functions[1] will be a good start to help you summarizes the rows of a group into a single value. They return a single result row based on groups of rows, rather than on single rows.

[1] https://cloud.google.com/bigquery/docs/reference/standard-sql/aggregate_functions

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