drill-up

grouping →
drill-up(
    expression: expression
) → grouping

Derives keys from existing grouping keys and merges matching groups into one grouping level.

Parameters

Name	Type	Required	Description
expression	expression	Yes	The expression that derives a new key from each existing group key.

Argument evaluation

Visits each existing key of the grouping supplied as pipeline input to this drill-up call, in group order, including keys of empty groups.

• expression: Evaluated once per existing key, with that key as its context; $0 reads the first component of a tuple key and .field reads a record key’s field.

Behavior

Structural equality includes null and tuple keys. Matching keys merge value collections in source-group order; new keys retain first-seen order, including keys from empty groups. Returns one grouping level, unlike roll-up, which produces multiple hierarchical levels.

Combine annual order lists into country lists

The first example groups order IDs by (country, year). drill-up($0) reads the country from each existing tuple key and combines the Belgian order lists across years. The order IDs remain unchanged and in source-group order; they contain no year field to re-evaluate.

Calculate country revenue across all years

The second example keeps individual order amounts under (country, year) keys. drill-up($0) first merges the amounts for each country, and summarize(sum) then calculates the totals: Belgium has 120 + 30 + 80 = 230, and France has 90. $0 refers to the country component of each existing key, not to an amount. This produces one country level; use roll-up when multiple hierarchical levels are needed.

Examples

#{
  (T("BE", 2025) => {"BE-001", "BE-002"}),
  (T("FR", 2025) => {"FR-001"}),
  (T("BE", 2026) => {"BE-003"})
}
| drill-up($0)
→ #{("BE" => {"BE-001", "BE-002", "BE-003"}), ("FR" => {"FR-001"})}

#{
  (T("BE", 2025) => {120, 30}),
  (T("FR", 2025) => {90}),
  (T("BE", 2026) => {80})
}
| drill-up($0)
| summarize(sum)
→ !{("BE" => 230), ("FR" => 90)}

Kind: Function
Scope: grouping
Aliases: None