listMembers throws "Incorrect syntax near ')'" on MSSQL when the filter matches zero members

Is this suited for github?

• Yes, this is suited for github

Reproduction

Reproduction

1. Create an organization with at least one member
2. Call listMembers with a filter matching zero rows — e.g. filterField: 'role', filterValue: 'admin' on an org that has only owners and members

Any filter matching zero rows reproduces it; role is just the easiest to hit.

Current vs. Expected behavior

What happens

Calling auth.api.listMembers with a filter that matches no members throws a SQL syntax error instead of returning an empty list:

Error: Incorrect syntax near ')'.

Cause

In packages/better-auth/src/plugins/organization/adapter.ts, listMembers fetches member rows and then looks up the corresponding users:

const users = await adapter.findMany<User>({
   model: "user",
   where: [{ field: "id", value: members[0].map((member) => member.userId), operator: "in" }],
   limit: members[0].length,
});

When the member query returns nothing, the in value is an empty array and the adapter emits IN (). SQL Server rejects that as a syntax error. Postgres and MySQL tolerate it, which is likely why it hasn't surfaced on other dialects.

limit: members[0].length also evaluates to 0 in this case, which some dialects reject independently.

Expected

{ members: [], total: }

Suggested fix

Return early when the member query is empty, before the user lookup. This also avoids an unnecessary query on empty pages.

Note

The admin plugin's listUsers is unaffected — it queries a single table, so no id list is interpolated. The issue is specific to the two-step member → user fetch here, and would apply anywhere else that pattern occurs.

What version of Better Auth are you using?

[email protected]

System info

{
  "system": {
    "platform": "linux",
    "arch": "x64",
    "version": "#136-Ubuntu SMP PREEMPT_DYNAMIC Wed Jul  1 21:53:05 UTC 2026",
    "release": "6.8.0-136-generic",
    "cpuCount": 8,
    "cpuModel": "Intel(R) Core(TM) i7-4785T CPU @ 2.20GHz",
    "totalMemory": "15.52 GB",
    "freeMemory": "2.81 GB"
  },
  "node": {
    "version": "v24.18.0",
    "env": "development"
  },
  "packageManager": {
    "name": "npm",
    "version": "12.0.1"
  },
  "frameworks": null,
  "databases": null,
  "betterAuth": {
    "version": "Unknown",
    "config": null
  }
}

Which area(s) are affected? (Select all that apply)

Backend, Client, Package

Auth config (if applicable)

import { betterAuth } from "better-auth"
export const auth = betterAuth({
  emailAndPassword: {  
    enabled: true
  },
});

Additional context

No response