Compare 2 sheets with particular columns

Hello,
hear is the situation,
sheet1 is having "item code (ex. 150007) in column A", and "Rack ID in column B (ex. AA001)"

& other side in sheet2 i have only item code item codes in column A & except column B all columns are full with other info,

so
i want to compare both sheets with column "A"(item code) and if any record mach the Rack ID from sheet1 must get copied in sheet2 in column B to the same item code.