20 lines
638 B
Text
20 lines
638 B
Text
declare option output:method 'json';
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(
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let $map := map { 'R': 'red', 'G': 'green', 'B': 'blue' }
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return (
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$map?* (: 1. returns all values; same as: map:keys($map) ! $map(.) :),
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$map?R (: 2. returns the value associated with the key 'R'; same as: $map('R') :),
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$map?('G','B') (: 3. returns the values associated with the key 'G' and 'B' :)
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),
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('A', 'B', 'C') => count(),
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for $country in db:open('factbook')//country
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where $country/@population > 100000000
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let $name := $country/name[1]
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for $city in $country//city[population > 1000000]
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group by $name
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return <country name='{ $name }'>{ $city/name }</country>
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)
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