Error calling system() within awk - bash

Question

I'm trying to execute a system command to find out how many unique references a csv file has in its first seven characters as part of a larger awk script that processes the same csv file. There are duplicate entries and I don't want awk to parse the whole file twice so I'm avoiding NR. The gist of this part of the script is:
#!/bin/bash
awk '
{
#do some stuff, then when finished, count the number of unique references
productFile="BusinessObjects.csv";
systemCall = sprintf( "cat %s | cut -c 1-7 | sort | uniq | wc -l", $productFile );
productCount=`system( systemCall )`-1; #subtract 1 to remove column label row
}' < BusinessObjects.csv
And the interpreter doesn't like it:
awk: cmd. line:19: ^ syntax error ./awkscript.sh: line 38: syntax error near unexpected token '('
./awkscript.sh: line 38: systemCall = sprintf( "cat %s | cut -c 1-7 | sort | uniq | wc -l", $productFile );
If I hard-code the system command
productCount=`system( "cat BusinessObjects.csv | cut -c 1-7 | sort | uniq | wc -l" )`-1;
I get:
./awkscript.sh: command substitution: line 39: syntax error near unexpected token '"cat BusinessObjects.csv | cut -c 1-7 | sort | uniq | wc -l"'
./awkscript.sh: command substitution: line 39: 'system( "cat BusinessObjects.csv | cut -c 1-7 | sort | uniq | wc -l" )'
Technically, I could do this outside of awk at the start of the shell script, store the result in a system variable, and then pass it to awk using -v, but it's not great for the readability of the awk script (it's a few hundred lines long). Do I have a space or quotes in the wrong place? I've tried fiddling, but I can't seem to present the call to system() in a way that the interpreter will accept. Finally, is there a more sensible way to do this?
Edit: the csv file is indeed semicolon-delimited, so it's best to cut using the delimiter rather than the number of chars (thanks!).
ProductRef;Data1;Data2;etc
1234567;etc;etc;etc
Edit 2:
I'm trying to parse a csv file whose first column is full of N unique product references, and create a series of associated HTML pages that include a "Page n of N" information field. It's (painfully obviously) the first time I've used awk, but it seemed like an appropriate tool for parsing csv files. I'm trying to hence count and return the number of unique references. At the shell
cut -d\; -f1 BusinessObjects.csv | sort | uniq | wc -l
works fine, but I can't get it working inside awk by doing
#!/bin/bash
if [ -n "$1" ]
then
productFile=$1
else
echo "Missing product file argument."
exit
fi
awk -v productFile=$productFile '
BEGIN {
FS=";";
productCount = 0;
("cut -d\"\;\" -f1 " productFile " | sort | uniq | wc -l") | getline productCount;
productCount -=1; #remove the column label row
}
{
print productCount;
}'
I get a syntax error on the cut code if I don't wrap the semicolon in \"\;\" and the script just hangs without printing anything when I do.

Answer 1

I don't remember that you can use backticks in awk.
productCount=`system( systemCall )`-1; #subtract 1 to remove column label row
You can read your output by not using system and running your command directly, and using getline instead:
systemCall | getline productCount
productCount -= 1
Or more completely
productFile = "BusinessObjects.csv"
systemCall = "cut -c 1-7 " productFile " | sort | uniq | wc -l"
systemCall | getline productCount
productCount -= 1
No need to use sprintf and include cat.
Assigning strings to variables is also optional. You can just have "xyz" | getline ....
sort | uniq can just be sort -u if supported.
Quoting may be necessary if filename has spaces or characters that may confuse the command.
getline may alter global variables differently from expected. See https://www.gnu.org/software/gawk/manual/html_node/Getline.html.

Answer 2

Could something like this be an option?
$ cat productCount.sh
#!/bin/bash
if [ -n "$1" ]
then
productCount=`cat $1 | cut -c 1-7 | sort | uniq | wc -l`
echo $productCount
else
echo "please supply a filename as parameter"
fi
$ ./productCount.sh BusinessObjects.csv
9