[backend/database] Fix votersCount getting set for all polls

Iceshrimp.Backend/Core/Database/Migrations/20240605135805_FixupPollVotersCounts.cs

@@ -0,0 +1,25 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+
+#nullable disable
+
+namespace Iceshrimp.Backend.Core.Database.Migrations
+{
+    /// <inheritdoc />
+    [DbContext(typeof(DatabaseContext))]
+    [Migration("20240605135805_FixupPollVotersCounts")]
+    public partial class FixupPollVotersCounts : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+	        migrationBuilder.Sql($"""UPDATE "poll" SET "votersCount" = NULL;""");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+
+        }
+    }
+}

Iceshrimp.Backend/Core/Services/PollService.cs

@@ -20,7 +20,7 @@ public class PollService(
 		{
 			if (!updateVotersCount) return;
 			await db.Database
-			        .ExecuteSqlAsync($"""UPDATE "poll" SET "votersCount" = (SELECT COUNT(*) FROM (SELECT DISTINCT "userId" FROM "poll_vote" WHERE "noteId" = {poll.NoteId}));""");
+			        .ExecuteSqlAsync($"""UPDATE "poll" SET "votersCount" = (SELECT COUNT(*) FROM (SELECT DISTINCT "userId" FROM "poll_vote" WHERE "noteId" = {poll.NoteId})) WHERE "noteId" = {poll.NoteId};""");
 			return;
 		}