base.join

Join two tables on one or more shared key columns. The binary counterpart to base.reduce_join (which gathers a map fan-in collection): use base.join to merge two independently-produced tables, e.g. a table of area estimates with a table of covariates. Overlapping non-key columns from the right table are suffixed with _right. Accepts CSV or Parquet input and emits Parquet output.

  • Kind: standard
  • Network: no

Inputs🔗

NameTypeDescription
leftfile (Parquet, CSV accepted)Left table. Its rows/columns lead.
rightfile (Parquet, CSV accepted)Right table. Because both inputs share the same type, a pipeline must wire them with explicit references that name the target input via as (e.g. as: left / as: right), not bare ones.
onstringComma-separated key column name(s) that must exist in both tables.
howstringJoin type - one of "inner" (default), "left", "right", or "outer".

Outputs🔗

NameTypeDescription
resultfile (Parquet)The joined table.

Example🔗

- id: 01890000-0000-0000-0000-00000000000f
  name: base.join
  inputs:
    - id: 01890000-0000-0000-0000-000000000000
      as: left
    - id: 01890000-0000-0000-0000-000000000001
      as: right
  args:
    on: "area_id"
    how: "inner"