rare usage of "that"

[hairstyler]

For I had never seen the following usage of "that", please help me describe the function of "that" in the following sentence:

Who that you have ever seen can do better ??



Thanks a million,
Hairstyler

[Joe Carillo]

I don’t think this sentence that you presented is constructed properly:

“Who that you have ever seen can do better?”

That sentence has faulty syntax, its construction is stilted, and its use of “that” as a relative pronoun is dysfunctional. In fact, that usage of “that” isn’t only rare; it isn’t a grammatically valid usage at all.

Here are four ways of constructing that sentence correctly:

“Who have you seen can do better?”
“Who among those you have seen can do better?”
“Have you ever seen someone who can do better?”
“Have you ever seen anybody who can do better?”