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MarkLogic 9 Product Documentation
op:col

op:col(
   [$plan as map:map],
   $colName as string
) as map:map

Summary

This method identifies a column, where the column name is unique. A qualifier on the column name isn't necessary (and might not exist). In positions where only a column name can appear, the unqualified column name can also be provided as a string. Qualified column names cannot be provided as a string.

Parameters
$plan The Optic AccessorPlan created by op:from-view, op:from-triples, or op:from-lexicons.
$colName The name of the column.

Example


xquery version "1.0-ml";

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

let $resource := op:prefixer("http://dbpedia.org/resource/")
let $foaf     := op:prefixer("http://xmlns.com/foaf/0.1/")
let $onto     := op:prefixer("http://dbpedia.org/ontology/")
let $person   := op:col("person")

return op:from-triples((
   op:pattern($person, $onto("birthPlace"), $resource("Brooklyn")), 
   op:pattern($person, $foaf("name"), op:col("name"))))
   => op:result()

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()

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