diff --git a/server/channelserver/repo_shop.go b/server/channelserver/repo_shop.go
index fd32c8a43..04f1c18f1 100644
--- a/server/channelserver/repo_shop.go
+++ b/server/channelserver/repo_shop.go
@@ -28,8 +28,7 @@ func (r *ShopRepository) GetShopItems(shopType uint8, shopID uint32, charID uint
 func (r *ShopRepository) RecordPurchase(charID, shopItemID, quantity uint32) error {
 	_, err := r.db.Exec(`INSERT INTO shop_items_bought (character_id, shop_item_id, bought)
 		VALUES ($1,$2,$3) ON CONFLICT (character_id, shop_item_id)
-		DO UPDATE SET bought = bought + $3
-		WHERE EXCLUDED.character_id=$1 AND EXCLUDED.shop_item_id=$2
+		DO UPDATE SET bought = shop_items_bought.bought + $3
 	`, charID, shopItemID, quantity)
 	return err
 }
diff --git a/server/channelserver/repo_shop_test.go b/server/channelserver/repo_shop_test.go
index 03a882c93..9a84b1070 100644
--- a/server/channelserver/repo_shop_test.go
+++ b/server/channelserver/repo_shop_test.go
@@ -57,14 +57,32 @@ func TestRepoShopGetShopItems(t *testing.T) {
 	}
 }
 
-func TestRepoShopRecordPurchaseAmbiguousColumn(t *testing.T) {
-	repo, _, charID := setupShopRepo(t)
+func TestRepoShopRecordPurchaseInsertAndUpdate(t *testing.T) {
+	repo, db, charID := setupShopRepo(t)
 
-	// RecordPurchase uses ON CONFLICT with unqualified "bought" column reference,
-	// which PostgreSQL rejects as ambiguous. This test documents the existing bug.
-	err := repo.RecordPurchase(charID, 1, 3)
-	if err == nil {
-		t.Fatal("Expected error from ambiguous column reference in RecordPurchase SQL, but got nil")
+	// First purchase inserts a new row
+	if err := repo.RecordPurchase(charID, 1, 3); err != nil {
+		t.Fatalf("RecordPurchase (insert) failed: %v", err)
+	}
+
+	var bought int
+	if err := db.QueryRow("SELECT bought FROM shop_items_bought WHERE character_id=$1 AND shop_item_id=$2", charID, 1).Scan(&bought); err != nil {
+		t.Fatalf("Verification query failed: %v", err)
+	}
+	if bought != 3 {
+		t.Errorf("Expected bought=3, got: %d", bought)
+	}
+
+	// Second purchase updates (adds to) the existing row
+	if err := repo.RecordPurchase(charID, 1, 2); err != nil {
+		t.Fatalf("RecordPurchase (update) failed: %v", err)
+	}
+
+	if err := db.QueryRow("SELECT bought FROM shop_items_bought WHERE character_id=$1 AND shop_item_id=$2", charID, 1).Scan(&bought); err != nil {
+		t.Fatalf("Verification query failed: %v", err)
+	}
+	if bought != 5 {
+		t.Errorf("Expected bought=5 (3+2), got: %d", bought)
 	}
 }
 
diff --git a/server/migrations/sql/0001_init.sql b/server/migrations/sql/0001_init.sql
index eec83adef..c5ac2b225 100644
--- a/server/migrations/sql/0001_init.sql
+++ b/server/migrations/sql/0001_init.sql
@@ -1220,6 +1220,9 @@ CREATE TABLE public.shop_items_bought (
     bought integer
 );
 
+CREATE UNIQUE INDEX IF NOT EXISTS shop_items_bought_character_item_unique
+    ON public.shop_items_bought (character_id, shop_item_id);
+
 
 --
 -- Name: shop_items_id_seq; Type: SEQUENCE; Schema: public; Owner: -
diff --git a/server/migrations/sql/0003_shop_items_bought_unique.sql b/server/migrations/sql/0003_shop_items_bought_unique.sql
new file mode 100644
index 000000000..52f0fb6c4
--- /dev/null
+++ b/server/migrations/sql/0003_shop_items_bought_unique.sql
@@ -0,0 +1,5 @@
+-- Add unique constraint required for ON CONFLICT upsert in RecordPurchase.
+-- Uses CREATE UNIQUE INDEX which supports IF NOT EXISTS, avoiding errors
+-- when the baseline schema (0001) already includes the constraint.
+CREATE UNIQUE INDEX IF NOT EXISTS shop_items_bought_character_item_unique
+    ON public.shop_items_bought (character_id, shop_item_id);