Posted by groupy on 05/31/06 08:54

Ok, here is a asample table representing the problem more clearly

A | B | C | D
-----------------
a1 b1 c1 d1
a1 b2 c2 d2
a3 b3 c1 d3
a4 b4 c4 d3
a5 b5 c5 d5
a6 b6 c6 d3

Tha duplications are:
row 1+2 in param A
row 1+3 in param C
row 3+4+6 in param D
only row 5 is unique in all parameters.
conclusion: row 1+2+3+4+6 are the same user
goal: to find all duplicated rows & to delete them all accept one
instance to leave.

Note:
Finding that row 1similar to 2 in A & deleting it will loose data
because we won't know that row 1 is ALSO similar to 3 on C & later on
finding that 3 is similar to 4 & 6 on D & so on

The simple time consuming (about 2 weaks) query to acomplish the task
is:
SELECT count(*),A.B,C,D
FROM tbl
GROUP BY A,B,C,D
HAVING count(*)>1

I THANK YOU ALL

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