SumX

Iterator

SumX(table, rowExpr)

The sanctioned door into row context: evaluates rowExpr for each row of the named table, then sums. Bare columns of the iterated table are legal inside the row expression — and only there. Aggregations, measure references, and context/time functions cannot appear per-row (SQX009/SQX014).

SumX is additive, so it composes under YTD/QTD/MTD and RollingSum.

When to use it

Line-level math that must happen before summing: Qty × Price, Amount − Discount, unit margin × units.
Weighted totals and weighted averages (divide two SumX results with Divide).

Example

GrossRevenue := SumX(Sales, Sales.Qty * Sales.Price)

// The classic weighted average
WeightedPrice := Divide(SumX(Sales, Sales.Qty * Sales.Price), Sum(Sales.Qty))

Under the hood

Row expressions compile to plain SQL inside the aggregate — no per-row loop, no context transition:

SquareX
Compiled SQL (simplified)

GrossRevenue := SumX(Sales, Sales.Qty * Sales.Price)

SELECT "Sales"."region",
       SUM("Sales"."qty" * "Sales"."price") AS "GrossRevenue"
FROM "sales" AS "Sales"
GROUP BY "Sales"."region"

Good to know

Row expressions reference the ITERATED table only — a column from another table is SQX014 (name that table as the iterator instead).
No context transition: [Measure] references are rejected per-row — reference the columns directly.