One try ..

Assume the posted data is in Sheet1,
cols A to E, data from row2 down

Using 3 empty cols to the right, say cols G to I, put:

In G2: =B2&"_"&D2
In H2: =IF(COUNTIF($G$2:G2,G2)1,"",G2)
In I2: =IF(H2="","",B2)

Select G2:I2, fill down until the last row of data

In another sheet
-----------
The B codes are listed in A1 down, viz.:

ABCABC
ABCDDD
etc

Put in B1: =COUNTIF(Sheet1!I:I,A1)
Copy down

Col B will return the desired counts for the codes in col A
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Rgds
Max
xl 97
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Singapore, GMT+8
xdemechanik
http://savefile.com/projects/236895
--
"BeSmart" wrote in message
...
I have a list of 900 entries and for each change of code in column B I
need
to know the number of publications used in D excluding the duplication, ie
for ABCABC there are 3 publications, for ABCDDD there are 4.

A B C D
ABC ABCABC A MELAGE
ABC ABCABC A MELAGE
ABC ABCABC A MELHER
ABC ABCABC A DOGHAN
ABC ABCDDD A MELAGE
ABC ABCDDD A MELAGE
ABC ABCDDD A SYDMOR
ABC ABCDDD A MELHER
ABC ABCDDD A BRICOU

In a separate area I will then have a list of B codes with the formula
next
to it that calculates the number of unique publications eg:

ABCABC 3
ABCDDD 4

Any help with the formula I should use would be greatly appreciated.
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Thank for your help
BeSmart