diff --git a/server/src/services/commentService.ts b/server/src/services/commentService.ts
index d3f57fe..b078aae 100644
--- a/server/src/services/commentService.ts
+++ b/server/src/services/commentService.ts
@@ -2,11 +2,10 @@ import prisma from '../lib/prisma';
 import { HttpError } from '../lib/httpError';
 import * as notificationService from './notificationService';
 import { logger } from '../lib/logger';
+import { findByIdOrDisplay } from './ticketService';
 
 export async function addComment(ticketIdOrDisplay: string, body: string, actorId: string) {
-  const ticket = await prisma.ticket.findFirst({
-    where: { OR: [{ id: ticketIdOrDisplay }, { displayId: ticketIdOrDisplay }] },
-  });
+  const ticket = await findByIdOrDisplay(ticketIdOrDisplay);
   if (!ticket) throw new HttpError(404, 'Ticket not found');
 
   const [comment] = await prisma.$transaction([
diff --git a/server/src/services/ticketService.ts b/server/src/services/ticketService.ts
index 3833922..729ab7b 100644
--- a/server/src/services/ticketService.ts
+++ b/server/src/services/ticketService.ts
@@ -75,10 +75,12 @@ async function generateDisplayId(): Promise<string> {
   }
 }
 
+const idOrDisplayWhere = (idOrDisplay: string): Prisma.TicketWhereInput => ({
+  OR: [{ id: idOrDisplay }, { displayId: idOrDisplay }],
+});
+
 export function findByIdOrDisplay(idOrDisplay: string) {
-  return prisma.ticket.findFirst({
-    where: { OR: [{ id: idOrDisplay }, { displayId: idOrDisplay }] },
-  });
+  return prisma.ticket.findFirst({ where: idOrDisplayWhere(idOrDisplay) });
 }
 
 export function buildTicketWhere(filters: TicketFilters): Prisma.TicketWhereInput {
@@ -143,7 +145,7 @@ export async function listTicketsPaged(filters: TicketFilters, pagination: Pagin
 
 export async function getTicket(idOrDisplay: string) {
   const ticket = await prisma.ticket.findFirst({
-    where: { OR: [{ id: idOrDisplay }, { displayId: idOrDisplay }] },
+    where: idOrDisplayWhere(idOrDisplay),
     include: ticketInclude,
   });
   if (!ticket) throw new HttpError(404, 'Ticket not found');
@@ -196,7 +198,7 @@ export async function updateTicket(
   }
 
   const existing = await prisma.ticket.findFirst({
-    where: { OR: [{ id: idOrDisplay }, { displayId: idOrDisplay }] },
+    where: idOrDisplayWhere(idOrDisplay),
     include: {
       category: true,
       type: true,