Do the above sentences have the same meaning?
Do the above sentences mean the same thing?
The second sentence looks grammatical and idiomatic to me, but what about the first sentence?
Do the above sentences have the same meaning?
Do the above sentences mean the same thing?
The second sentence looks grammatical and idiomatic to me, but what about the first sentence?
Both of the above sentences are alike. They have the same meaning and they mean the same thing.
Asking if two sentences "have the same meaning" or "mean the same thing" is essentially equivalent. There is no outright grammar error in either of the proposed sentences. Some might say that the word "thing" is not necessary in the second sentence.
Do the sentences above have the same meaning?
Do the sentences above mean the same thing?
They mean exactly the same thing.
However, I prefer the verb form myself.