The difference between select and selectMany can be seen when we are accessing data from multilevel classes.
In the below example we shall see what exactly is the difference while accessing the properties.
When we access some data by using select it gives us the data that is grouped under the parent (i.e gives multiple arrays). To access the output we need to loop twice.
But using the same sample when we use select many it gives the selected items in one array(i.e it give the output as it is joining all the output from select command)