I am having problems understanding the expected results. For example, how can you get one hit from the last line? 
KAAVAIN TIZIT 620-20 H10;TASOKAAVAIN SANDVIK 620-25

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So far as I can see, none of the "words" in the first column appear in the second. But it does depend on what you mean by a "word". Can you please explain the match criteria?

Update: This is what I came up with:
#!/usr/bin/perl 
use strict;
use warnings;  

my $readfile = 'blah.csv';
my $writefile = 'bleh.csv';

# Note that you were opening $writefile for READ
open my $fh, "<", $readfile or die "Unable to open $readfile: $!";
open my $wfh, ">", $writefile or die "Unable to open $writefile: $!";

foreach (<$fh>) { 
    
    $_ = uc $_;
    chomp;
    
    my ($col1, $col2) = split /;/;
    my @col1_words = split /\s+/, $col1;
    my @col2_words = split /\s+/, $col2;
    
    my %hash;
    @hash{@col1_words} = undef;
    
    my $found = 0;
    for my $word (@col2_words) {
        $found++ if exists $hash{$word}
    }
    
    print $wfh "$_;".@col1_words.";$found\n";
    
}

close ($fh);
close ($wfh);

[download]
Which produces:
SUUTIN STAMM 2/60AST;SUUTIN STAMM 2,0/60 AST.           VIIRAOSA (PK-1
+);3;2
SUUTINKÄRKI SPRAY TP 9501 E-SS;SUUTIN  VALME HOL0125624 TP 9501    E-S
+S;5;3
O-RENGAS 790X12 FPM;UPPOPUMPPU PUMPEX KV56;3;0
O-RENGAS 99X7 FPM;RULLAUSPÄÄ B NORMAALI;3;0
KÄSISAHA SANDV 2600-22-XT L=22IN;KÄSISAHA 22 IN 2600-22-XT          SA
+NDVIK;4;2
VEITSI STANL 10-010;MATTOVEITSI STANLEY 2-10-099 99E;3;0
VEITSENTERÄ STANL 11-916 L=62MM SUORA;MATTOVEITSENTERÄ  STANLEY 0-11-9
+21    (5KPL/PAK)  PITT. 49;5;0
KAAVAIN TIZIT 620-20 H10;TASOKAAVAIN SANDVIK 620-25;4;0

[download]
Further update corrected typo.

In reply to Re: comparing columns and printing a result by cdarke
in thread comparing columns and printing a result by slartsa

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