In Google Sheets, I have a sheet with a list of customers.
Row 1 has headers, and data starts in row 2.
Column A is Customer name,
Column B is street address,
Column C is City and Post Code,
Column D is Country.

I would like to count the number of occurrences of each customer's record, i.e. when A, B, C, D are the same as a composite key.

However, I want to count different occurrences of a row ONLY IF those occurrences are not adjacent / concurrent, i.e.
I do want to count separate occurrences if row 5 and 7 have the same customer,
but not if row 5 and 6 have the same customer...in this case I will count it as one occurrence

e.g.
row 5:
A. London Eye
B. Riverside Building, County Hall,
C. London SE1 7PB
D. United Kingdom
row 6:
A. London Eye
B. Riverside Building, County Hall,
C. London SE1 7PB
D. United Kingdom
row 7:
A. London Eye
B. Riverside Building, County Hall,
C. London SE1 7PB
D. United Kingdom
COUNT: 1

row 5:
A. London Eye
B. Riverside Building, County Hall,
C. London SE1 7PB
D. United Kingdom
row 7:
A. London Eye
B. Riverside Building, County Hall,
C. London SE1 7PB
D. United Kingdom
row 9:
A. London Eye
B. Riverside Building, County Hall,
C. London SE1 7PB
D. United Kingdom
COUNT: 3

row 5:
A. London Eye
B. Riverside Building, County Hall,
C. London SE1 7PB
D. United Kingdom
row 6:
A. London Eye
B. Riverside Building, County Hall,
C. London SE1 7PB
D. United Kingdom
row 8:
A. London Eye
B. Riverside Building, County Hall,
C. London SE1 7PB
D. United Kingdom
COUNT: 2

Sample sheet:

Explanation Pending

1 - Search_key of the

2.a - To get the left column we need ArrayFormula(CONCAT(CONCAT(QUERY(UNIQUE(A2:B)," Select Col1 where Col1 is not null ")," "),QUERY(UNIQUE(A2:B)," Select Col2 where Col1 is not null ")))

• We get the UNIQUE(A2:B) and QUERY only non empty Col1 values with the query set to " Select Col1 where Col1 is not null "

• concatenate the output with CONCAT function with " " like this CONCAT(QUERY(UNIQUE(A2:B)," Select Col1 where Col1 is not null ")," ")

• once more concatenate the output with CONCAT function with " " like this CONCAT(CONCAT(QUERY(UNIQUE(A2:B)," Select Col1 where Col1 is not null ")," "),QUERY(UNIQUE(A2:B)," Select Col2 where Col1 is not null "))

• wrapped in a ArrayFormula Like this ArrayFormula(Output)

2.b - To get the right column we need QUERY(SEQUENCE(COUNTA(ArrayFormula(CONCAT(CONCAT(QUERY(UNIQUE(A2:B)," Select Col1 where Col1 is not null ")," "),QUERY(UNIQUE(A2:B)," Select Col2 where Col1 is not null ")))),1,1,1)

• Create a SEQUENCE With rows set to the COUNTA of the Output of step 2.b which is ArrayFormula(CONCAT(CONCAT(QUERY(UNIQUE(A2:B)," Select Col1 where Col1 is not null ")," "),QUERY(UNIQUE(A2:B)

• [columns] Set to 1.

• [start] Set to 1.

• [step] Set to 1.

• QUERY Col1 of the Output of SEQUENCE with query set to " Select * where Col1 is not null ".

3 - Set the index of VLOOKUP to 2 and [is_sorted] to 0.