| `author_id` | integer | no | Returns merge requests created by the given user `id`. Mutually exclusive with `author_username`. _([Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/13060) in GitLab 9.5)_. |
| `author_username` | string | no | Returns merge requests created by the given `username`. Mutually exclusive with `author_id`. _([Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/13060) in GitLab 12.10)_. |
| `assignee_id` | integer | no | Returns merge requests assigned to the given user `id`. `None` returns unassigned merge requests. `Any` returns merge requests with an assignee. _([Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/13060) in GitLab 9.5)_. |
| `approver_ids`**(PREMIUM)** | integer array | no | Returns merge requests which have specified all the users with the given `id`s as individual approvers. `None` returns merge requests without approvers. `Any` returns merge requests with an approver. |
| `approver_ids`**(PREMIUM))** | integer array | no | Returns merge requests which have specified all the users with the given `id`s as individual approvers. `None` returns merge requests without approvers. `Any` returns merge requests with an approver. |
| `approved_by_ids`**(PREMIUM)** | integer array | no | Returns merge requests which have been approved by all the users with the given `id`s (Max: 5). `None` returns merge requests with no approvals. `Any` returns merge requests with an approval. |
| `reviewer_id` | integer | no | Returns merge requests which have the user as a [reviewer](../user/project/merge_requests/getting_started.md#enable-or-disable-merge-request-reviewers) with the given user `id`. `None` returns merge requests with no reviewers. `Any` returns merge requests with any reviewer. Mutually exclusive with `reviewer_username`. |
| `reviewer_username` | string | no | Returns merge requests which have the user as a [reviewer](../user/project/merge_requests/getting_started.md#enable-or-disable-merge-request-reviewers) with the given `username`. `None` returns merge requests with no reviewers. `Any` returns merge requests with any reviewer. Mutually exclusive with `reviewer_id`. |
| `reviewer_id` | integer | no | Returns merge requests which have the user as a [reviewer](../user/project/merge_requests/getting_started.md#reviewer) with the given user `id`. `None` returns merge requests with no reviewers. `Any` returns merge requests with any reviewer. Mutually exclusive with `reviewer_username`. |
| `reviewer_username` | string | no | Returns merge requests which have the user as a [reviewer](../user/project/merge_requests/getting_started.md#reviewer) with the given `username`. `None` returns merge requests with no reviewers. `Any` returns merge requests with any reviewer. Mutually exclusive with `reviewer_id`. |
| `my_reaction_emoji` | string | no | Return merge requests reacted by the authenticated user by the given `emoji`. `None` returns issues not given a reaction. `Any` returns issues given at least one reaction. _([Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/14016) in GitLab 10.0)_. |
| `source_branch` | string | no | Return merge requests with the given source branch. |
| `target_branch` | string | no | Return merge requests with the given target branch. |