From bcf585b1cfba4354989c828a3ecb3168f3eae8b9 Mon Sep 17 00:00:00 2001
From: Santo Cariotti <santo@dcariotti.me>
Date: Sat, 6 Feb 2021 22:16:00 +0100
Subject: databases: ex 3

---
 Year_2/Databases/university_marks.xquery     | 11 -----------
 Year_2/Databases/university_marks_ex2.xquery | 12 ++++++++++++
 Year_2/Databases/university_marks_ex3.xquery | 15 +++++++++++++++
 3 files changed, 27 insertions(+), 11 deletions(-)
 delete mode 100644 Year_2/Databases/university_marks.xquery
 create mode 100644 Year_2/Databases/university_marks_ex2.xquery
 create mode 100644 Year_2/Databases/university_marks_ex3.xquery

diff --git a/Year_2/Databases/university_marks.xquery b/Year_2/Databases/university_marks.xquery
deleted file mode 100644
index e2f0e4e..0000000
--- a/Year_2/Databases/university_marks.xquery
+++ /dev/null
@@ -1,11 +0,0 @@
-<students>
-{
-for $student in doc("university_marks.xml")//libretto
-where $student/esami//voto/text()=30
-return <student>
-    {$student/studente/nome/text()}
-    { ' ' }
-    {$student/studente/cognome/text()}
-    </student>
-}
-</students>
diff --git a/Year_2/Databases/university_marks_ex2.xquery b/Year_2/Databases/university_marks_ex2.xquery
new file mode 100644
index 0000000..e75616c
--- /dev/null
+++ b/Year_2/Databases/university_marks_ex2.xquery
@@ -0,0 +1,12 @@
+<ex2>
+{
+for $student in doc("university_marks.xml")//libretto
+where $student/esami//voto/text()=30
+return <student>
+    {$student/studente/nome/text()}
+    { ' ' }
+    {$student/studente/cognome/text()}
+    </student>
+}
+</ex2>
+
diff --git a/Year_2/Databases/university_marks_ex3.xquery b/Year_2/Databases/university_marks_ex3.xquery
new file mode 100644
index 0000000..dd1f5b8
--- /dev/null
+++ b/Year_2/Databases/university_marks_ex3.xquery
@@ -0,0 +1,15 @@
+<ex3>
+{
+let $f := doc("university_marks.xml")
+let $courses := distinct-values($f//materia)
+
+for $course in $courses
+return <course area="{$course}">
+    {
+    for $data in $f//libretto
+    where $data//esami//esame//materia/text()=$course
+    return <student>{$data//studente/@matricola}</student>
+    }
+    </course>
+}
+</ex3>
-- 
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