[SalesForce] Wave Analytics, Analytics cloud and Einstien Analytics different

Wave analytics is a new cloud based analytic tool that will help you to create powerful reports and dashboards from your large amount of enterprise data .The data may be inside SFDC or may reside in your external system .

The best place to get started is using Trailhead .Below are some of Trailhead modules that will get you started .Also you will get a free developer instance for playing around

Wave Basics

Wave Desktop Exploration

Wave mobile Exploration

If you are working with salesforce as a partner then there are specific trainings you would like to get

1)White belt 2)Green belt 3)Brown belt

There are chatter groups on patner portal where you can find all helpful documentation .Once you complete Green belt you get a free org for practice .

This is possible, SAQL has a cogrouping function which allows you to join two or more datasets together. This allows for both inner and outer joins.

https://developer.salesforce.com/docs/atlas.en-us.bi_dev_guide_saql.meta/bi_dev_guide_saql/bi_saql_statement_group.htm

Another option is to pull the data into Wave using a Dataflow, here you can use the Augment function however at the moment the types of join that can be done in the Dataflow are more limited, e.g. for multiple matches, the only option is the have the returned results in a comma separated list rather than multiple rows.

https://resources.docs.salesforce.com/200/latest/en-us/sfdc/pdf/bi_admin_guide_data_integration_guide.pdf

Filtering is possible in both the Dataflow and SAQL.

I would use the dataflow to join the datasets to the required form as far as is possible, and then use SAQL to join where the Dataflow does not provide you with the required type of joins.