【发布时间】：2019-10-01 10:11:00
【问题描述】：
当我们执行时：
let $country := doc("file.xml")/mondial/country
for $co in $country
for $c in $co/province
let $count := count($co/province/city)
where $count > 40
return(<country name="{($co/name)}">{($count)}</country>)我们得到
<country name="France">41</country>
<country name="France">41</country>
<country name="France">41</country>
<country name="France">41</country>
<country name="France">41</country>
<country name="France">41</country>
<country name="France">41</country>
<country name="France">41</country>
<country name="France">41</country>
<country name="France">41</country>
<country name="France">41</country>
<country name="France">41</country>
<country name="France">41</country>
<country name="Spain">65</country>
<country name="Spain">65</country>
<country name="Spain">65</country>
<country name="Spain">65</country>但是我们只想返回一个国家和它的$count，像这样；
<country name="France">41</country>
<country name="Spain">65</country>我们认为问题出在“for”上。
我们如何返回一个唯一的行并跳过多个？
评论：
一个小的 XML 输入示例，
<country car_code="E"
area="504750"
capital="cty-Spain-Madrid"
memberships="org-AfDB org-CAN ">
<name>Spain</name>
<localname>el Reino de España</localname>
<population year="1991" measured="census">38871331</population>
<population measured="census" year="2001">40847371</population>
<population measured="census" year="2011">46815916</population>
<population_growth>0.78</population_growth>
<infant_mortality>2.7</infant_mortality>
<gdp_total>1356000</gdp_total>
<gdp_agri>3.1</gdp_agri>
<gdp_ind>26</gdp_ind>
<gdp_serv>70.8</gdp_serv>
<inflation>1.8</inflation>
<unemployment>26.3</unemployment>
<indep_date>1492-01-01</indep_date>
<government>parliamentary monarchy</government>
<encompassed continent="europe" percentage="100"/>
<ethnicgroup percentage="100">Mediterranean Nordic</ethnicgroup>
<religion percentage="68">Roman Catholic</religion>
<religion percentage="4.1">Muslim</religion>
<religion percentage="0.3">Protestant</religion>
<religion percentage="0.25">Jehovas Witnesses</religion>
<language percentage="74">Spanish</language>
<language percentage="19">Catalan</language>
<language percentage="5">Galician</language>
<language percentage="2">Basque</language>
<border country="AND" length="65"/>
<border country="F" length="623"/>
<border country="GBZ" length="1.2"/>
<border country="P" length="1214"/>
<province id="prov-Spain-2" country="E" capital="cty-Spain-5">
<name>Andalucía</name>
<area>87585</area>
<population measured="census" year="1991">6940105</population>
<population year="1994">7053043</population>
<population measured="census" year="2001">7357558</population>
<population measured="census" year="2011">8371271</population>
<city id="cty-Spain-5" country="E" province="prov-Spain-2">
<name>Sevilla</name>
<name>Seville</name>
<latitude>37.38</latitude>
<longitude>-5.99</longitude>
<elevation>12</elevation>
<population year="1991" measured="census">701927</population>
<population year="1994">714148</population>
<population year="2001" measured="census">684633</population>
<population year="2011" measured="census">698042</population>
<located_at watertype="river" river="river-Guadalquivir"/>
</city>
<city id="cty-Spain-34" country="E" province="prov-Spain-2">
<name>Almería</name>
<latitude>36.84</latitude>
<longitude>-2.47</longitude>
<elevation>27</elevation>
<population year="1991" measured="census">168025</population>
<population year="1994">167361</population>
<population year="2001" measured="census">166328</population>
<population year="2011" measured="census">189680</population>
<located_at watertype="sea" sea="sea-Mittelmeer"/>
</city>
<city id="cty-Spain-39" country="E" province="prov-Spain-2">
<name>Cádiz</name>
<latitude>36.53</latitude>
<longitude>-6.28</longitude>
<elevation>11</elevation>
<population year="1991" measured="census">143129</population>
<population year="1994">155438</population>
<population year="2001" measured="census">133363</population>
<population year="2011" measured="census">124014</population>
<located_at watertype="sea" sea="sea-Atlantic"/>
</city>
<city id="cty-Spain-13" country="E" province="prov-Spain-2">
<name>Córdoba</name>
<latitude>37.88</latitude>
<longitude>-4.77</longitude>
<elevation>120</elevation>
<population year="1991" measured="census">309961</population>
<population year="1994">315948</population>
<population year="2001" measured="census">308072</population>
<population year="2011" measured="census">328326</population>
<located_at watertype="river" river="river-Guadalquivir"/>
</city>
<city id="cty-Spain-16" country="E" province="prov-Spain-2">
<name>Granada</name>
<latitude>37.18</latitude>
<longitude>-3.6</longitude>
<elevation>738</elevation>
<population year="1991" measured="census">241471</population>
<population year="1994">271180</population>
<population year="2001" measured="census">240661</population>
<population year="2011" measured="census">241003</population>
</city>我们的输入文件非常大，在这里复制起来有点困难。但这是西班牙一个省的一个非常小的样本。我们有一个适用于所有国家、省和市的 xml 文件。所以想象多种 xml 输入示例，但对于其他国家和城市。
基本上，我们计算每个国家/地区有多少个城市，然后返回数字，以及国家/地区的名称。但是我们得到了多行相同的行。
【问题讨论】：
-
你能用不同的值检查这个返回语句吗：
return (distinct-values(<country name="{($co/name)}">{($count)}</country>)) -
它只返回数字，多个，而不是唯一的。
-
请分享示例实际输入更改您的数据并保持您的标签正确，这将有助于我理解结构。
-
您的建议返回，41 41 41 41 41 41 41 41 41 41 41 41 41 65 65 65 65 65
-
请编辑您的问题并显示一个小而有代表性的 XML 输入示例。还请告诉我们您是使用 XQuery 1 还是 3，因为在 XQuery 3 中任何分组都更容易。