Erm . . .

A) Go read How (Not) To Ask A Question now before posting another incomprehensible question.

B) You either need to read about the different quoting operators in perlop if you're backwhacking "s or 's, or you're trying to ask about placeholders which are covered in the DBI documentation. But your question is so vague and those are only enormously wild guesses so who knows (again, see point A above).