Grey fields in table

[Timwalker]

When attempting to make a relationship between 2 tables, some fields ( 2 actually) are grey and not selectable.

Why is this?

[Lee Smith]

I suspect it is because of their field type. Are they Summary?

[Timwalker]

Yes

[Lee Smith]

Summary functions produce a summary of all records in the found set

Since this is a moving target, it can't be used in a Relationship. Read more here.

Summary Fields

[Timwalker]

Thanks!

After reading a bit, seems like it is beyond my skills.