From 03ccfe7611795473117ab0b5922e15660f555d07 Mon Sep 17 00:00:00 2001
From: Antti Leinonen <antti.leinonen@helsinki.fi>
Date: Fri, 23 Jan 2026 16:11:12 +0200
Subject: [PATCH 1/2] Remove duplicates from downloaded completion lists

---
 backend/api/routes/completions.ts | 29 ++++++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/backend/api/routes/completions.ts b/backend/api/routes/completions.ts
index 2f8e05414..e203d2ddd 100644
--- a/backend/api/routes/completions.ts
+++ b/backend/api/routes/completions.ts
@@ -205,11 +205,7 @@ export class CompletionController extends Controller {
       .join("course as c", "com.course_id", "c.id")
       .join("user as u", "com.user_id", "u.id")
       .where("c.id", course.completions_handled_by_id ?? course.id)
-      .distinct("u.id", "com.course_id")
       .orderBy("com.completion_date", "asc")
-      .orderBy("u.last_name", "asc")
-      .orderBy("u.first_name", "asc")
-      .orderBy("u.id", "asc")
 
     if (fromDate && typeof fromDate === "string") {
       try {
@@ -222,6 +218,27 @@ export class CompletionController extends Controller {
 
     const completions = await query
 
+    // Filter to keep only the oldest completion per user (already sorted by completion_date asc)
+    const seenUsers = new Set<string>()
+    const uniqueCompletions = completions.filter((row) => {
+      if (seenUsers.has(row.id)) {
+        return false
+      }
+      seenUsers.add(row.id)
+      return true
+    })
+
+    // Sort by usuniqueCr name and ID
+    uniqueCompletions.sort((a, b) => {
+      if (a.last_name !== b.last_name) {
+        return (a.last_name || "").localeCompare(b.last_name || "")
+      }
+      if (a.first_name !== b.first_name) {
+        return (a.first_name || "").localeCompare(b.first_name || "")
+      }
+      return a.id.localeCompare(b.id)
+    })
+
     const headers = [
       "User ID",
       "Email",
@@ -237,7 +254,9 @@ export class CompletionController extends Controller {
       row.email,
       row.first_name,
       row.last_name,
-      row.completion_date,
+      row.completion_date
+        ? new Date(row.completion_date).toISOString()
+        : row.completion_date,
       row.completion_language,
       row.grade,
     ])

From 7d0793cc5b7a93bb2d953bf4baf6a528f07b65c8 Mon Sep 17 00:00:00 2001
From: Antti Leinonen <antti.leinonen@helsinki.fi>
Date: Fri, 23 Jan 2026 16:50:05 +0200
Subject: [PATCH 2/2] Obey the rabbit

---
 backend/api/routes/completions.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/backend/api/routes/completions.ts b/backend/api/routes/completions.ts
index e203d2ddd..9bf93c62a 100644
--- a/backend/api/routes/completions.ts
+++ b/backend/api/routes/completions.ts
@@ -228,7 +228,7 @@ export class CompletionController extends Controller {
       return true
     })
 
-    // Sort by usuniqueCr name and ID
+    // Sort by last name, first name, and ID
     uniqueCompletions.sort((a, b) => {
       if (a.last_name !== b.last_name) {
         return (a.last_name || "").localeCompare(b.last_name || "")
@@ -249,7 +249,7 @@ export class CompletionController extends Controller {
       "Grade",
     ]
 
-    const rows = completions.map((row) => [
+    const rows = uniqueCompletions.map((row) => [
       row.id,
       row.email,
       row.first_name,