op:on

op:on(
   $leftCol as item(),
   $rightCol as item()
) as map:map

Summary

Specifies an equijoin using one columndef each from the left and right rows. The result is used by the op:join-inner, op:join-left-outer, and op:join-full-outer, and functions.

Use op:view-col or op:col if you need to identify columns in the two views that have the same column name.

The default collation for string values in a TDE template is codepoint. If you are having problems joining columns that use a different collation, you will need to change the TDE template to use a matching collation, or change the appropriate range indexes to use codepoint.

Parameters
$leftCol	The rows from the left view.
$rightCol	The row set from the right view.

Example

xquery version "1.0-ml";

import module namespace op="http://marklogic.com/optic"
     at "/MarkLogic/optic.xqy";

let $employees := op:from-view("main", "employees")
let $expenses  := op:from-view("main", "expenses")
let $totalexpenses  := op:col("totalexpenses")
return $employees
   => op:join-inner($expenses, op:on(
                    op:view-col("employees", "EmployeeID"),
                    op:view-col("expenses", "EmployeeID")))
   => op:group-by(op:view-col("employees", "EmployeeID"),
                 ("FirstName", "LastName",
                  op:view-col("expenses", "Category"),
                  op:sum($totalexpenses,
                  op:view-col("expenses", "Amount"))))
   => op:order-by(op:view-col("employees", "EmployeeID"))
   => op:result()