Our Post Grid Combo plugin will help you query posts by Post Parent. By reading this article, you’ll get a clear idea about how to query posts by post parent.
Click and expand the Query Post tab.

Now, click on Post Type and select Pages.

Now search for the “Parent” by using the Choose button. Here you will find three options; click your desired option.

For Post Parent:
The post parent dropdown tab is accessible by selecting the post parent. Now click and enter the Parent Page ID. The entered Parent Page ID will change your Post Grid.

For Post Parent In:
Here type the Parent Page IDs separated by a comma. The post grid is then updated with the specified Parent Page ID.

For Post Parent Not in:
Here type the Parent Page ID. Now The post grid hides all the posts of the specified Parent ID.
