[Rust] [DataFusion] Add join support to DataFrame and LogicalPlan

[asfimport]

Add join support to DataFrame and LogicalPlan.

Logical Plan

My initial thoughts on the design of the LogicalPlan struct would be:

struct InnerJoin {
  left: Box<LogicalPlan>,
  right: Box<LogicalPlan>,
  left_keys: Vec<Expr>,
  right_keys: Vec<Expr>
} 

The left_keys and right_keys vectors must have the same length. Example pseudo-code:

let join = InnerJoin {
  left: read_parquet("customers"),
  right: read_parquer("orders"),
  left_keys: vec![col("id")],
  right_keys: vec![col("customer_id")]
};    

DataFrame

let customer = ctx.read_parquet("customers").alias("c");
let orders = ctx.read_parquet("orders").alias("o");

// generic join method that can support all types of join
let join = customer.join(orders, col("c.id").eq("o.customer_id"))

// or we could start with a more specific equijoin method
let join = customer.inner_join(orders, vec![col("id")], vec![col("customer_id")]);

 

 

 

 

Reporter: Andy Grove / @andygrove
Assignee: Andy Grove / @andygrove

PRs and other links:

• GitHub Pull Request #8720

_{Note: This issue was originally created as ARROW-10585. Please see the migration documentation for further details.}

[asfimport]

Andy Grove / @andygrove:
Issue resolved by pull request 8720
#8720