You would've passed if you had you studied more

[Glizdka]

I've noticed that 'had' can be used in the same position 'if' is used in conditional sentences.

(1) "You would've passed if you had studied more."
(2) "You would've passed had you studied more."
(3) "You would've passed, had you studied more."

Does this mean 'had' effectively functions as a conjunction in sentence 2? I'm not sure, but I don't think it's the case because the past participle is necessary, so 'had' must be the auxiliary. The other option I can think of is that it's auxiliary-subject inversion, in which case there should be a comma between the two clauses (as in sentence 3).

The same question goes for 'should' (though it doesn't necessitate using the past participle).

(1) "We still have plenty if you should need one."
(2) "We still have plenty should you need one."
(3) "We still have plenty, should you need one."

Could you help me out?

 

[PaulMatthews]

No, "had" is not a subordinator (your conjunction).

Normally a conditional adjunct has the form of a preposition phrase with "if" as head and a content clause as complement, as in [1]. (2) is the equivalent of [1], but "if" has been omitted and replaced by a content clause with subject-auxiliary inversion. The comma is optional and has no effect on the syntax.

The meaning remains unchanged.