Bring related rows together with a join

An order stores a carrier code; a carrier entity stores the carrier’s display name. An inner join returns rows only where the join condition matches on both sides.

State the relationship

SELECT FROM zi_dispatch_order AS orders
  INNER JOIN zi_carrier AS carriers
    ON orders~carriercode = carriers~carriercode

Aliases make multi-source statements easier to read. The ~ separator qualifies fields by their source alias and avoids ambiguity when both sources have similarly named fields.

Select explicitly from both sides

FIELDS orders~dispatchorder, carriers~carriername
INTO TABLE @DATA(order_carriers).

An inner join excludes orders without a matching carrier. That is correct only if unmatched orders should be excluded. If they must remain, consider an outer join and handle the missing side.

Join or CDS association?

Use a join in a query when you need the combination for this read. A CDS association models a reusable relationship in a view definition and can be navigated by consumers. Choose based on whether the relationship itself should be part of a reusable model.

Practice

Add the matching inner join, qualified fields, and table target. Set result to the row count. This checker does not execute the query.

Sources

• SAP Samples, ABAP SQL
• SAP Samples, CDS View Entities
• SAP Help Portal, ABAP SQL

Version note: Join forms and syntax support depend on source type and ABAP release.

SELECT FROM zi_dispatch_order AS orders
  INNER JOIN zi_carrier AS carriers
    ON orders~carriercode = carriers~carriercode
  FIELDS orders~dispatchorder, carriers~carriername
  INTO TABLE @DATA(order_carriers).
DATA(result) = lines( order_carriers ).

WRITE result.

out->write( result ).