Comparing column values?

col1        | col2      | col3 : col2 + col1 | col4 : unique col3   
93 	|1030800	 |1030800 93	   | 1030800 93
93	|1030800	 |1030800 93	
052	|1030800 |1030800 052	   | 1030800 052

I have to find out if there are more then one unique col3 values for each value of col2. I try this by inserting a formula in col 4

=IF(COUNTIF($W$3:W3;InStr(W3;U3)>1);"morethen1";"")

the logic is : count the number of non empty cells in col4 : unique col3 where a part of the value of col 3 (InStr) is equal to col 2. While testing I try to use only the InStr function, but he produce the error of #NAME and up to now the formula =IF(COUNTIF($W$3:W3;InStr(W3;U3)>1);"morethen1";"") is not working.

I discovered how to fix this. In your Worksheet you need to work with the FIND methode instead of the InStr

=IF(W3<>"";LEFT(W3;FIND(" ";W3;1)-1);"")