Excel 2007 : copy number from one to many

[excelistdsm]

Hi,

I have an excel workbook with 2 worksheets. The setup of 'Sheet1':

DAY	CODE	JUSTSOMEDATA
15		A
15		A
15		B
16		B
16		C
16		A
17		B
17		B
17		A
18		B
18		B
18		A

The setup of 'Sheet2':

MONTH	DAY	CODE
JUNE	15	2
JUNE	16	2
JUNE	17	1
JUNE	18	2

I have multiple workbooks, about 120,000+ rows for the combined total of 'Sheet1' among all workbooks. So I'm looking for an efficient way to copy over the CODE column number in 'Sheet2' that corresponds to the DAY column in 'Sheet1'. The day for 2 workbooks begins at 15 and the remaining workbooks begins at 0. Help me excelforum, you're my only hope.

[nlm]

Have you tried vlookup in sheet1 like:
vlookup('day',sheet2!day1:code4,2,false)

nlm.