The second sentence is in the past and means it would probably not be worth the customer going to Isle 14.If somebody is asking me about an item in the store and I am not sure if we have it or not, what should I say?
If we have it, it will be on isle 14
If we had it, it would have been on isle 14
Well, not really, FF. If it was in the past it would be:The second sentence is in the past and means it would probably not be worth the customer going to Isle 14.
The subjunctive is not a tense, but a mood. The second sentence is not, in fact, in the subjunctive; the present subjunctive takes the form of the bare infinitive, and so the present subjunctive form of "have" is not "had", but "have". This means that the sentence which may actually be in the present subjunctive is the first one: If we have it....The second sentence, "If we had it, it would be on aisle 14," is in the subjunctive tense.
Whatever our differences, Alex, I suppose they are a matter of terminology mostly. Some people see the subjunctve mood every time a past-tense verb form is used to express an impossible scenario. I am not one of them. According to the grammar I have been taught and believe in, conditionals and the subjunctive mood are two separate distinct categories. Not to mention the fact that, according to many grammarians, the conditional mood is a mood in its own right. I therefore decline politely, but firmly, to accept the two sentences here as examples of the subjunctive. Even if I have to die a martyr's death for this.Boozer the second conditional is , as you said, past tense + would, but the "past tense" we see, is not Indicative mood but Subjunctive in its past form. Pratically , apart the verb "to be" they're the same We can use the Subjunctive to express impossible or just unlikely scenarios.The first conditional is simple present (Indicative mood) in the if clause plus the future simple "will". I found this http://web.cn.edu/kwheeler/grammar_subjunctive.html
That explains the distinction well.It can be used for situations other than something contrary to fact. It's also used for hypothetical statements. That's how I would read this. In other words, the clerk is saying "I don't know for sure that we have it, but I do know how products are organized in the store. In the hypothetical situation that we had it (not past tense but subjunctive), it would be on aisle 14."
The implication I would get from the first sentence is that there have been times when the product was stocked. The clerk doesn't know if there is any in stock right now.
The implication I would get from the second sentence is that the clerk is not even certain that the store carries such a product. If the product is carried and is available it will be found on aisle 14.