If how to output 0 if Awk didn't find a value?

Question

linux

How to make awk output 0 if it didn't find a value in a file?
cat /countCodes | awk ' /'$1'/ {print $1} '
Search goes by file

742401 200
   9553 404
   8594 304
   8490 301
    403 499
    311 302
     10 500
      7 408
      4 503
      3 400
3206 access_postdata.log

The script looks for a code like 500 and displays the value 10

Answer 1

what value are you looking for? You don't actually "search" - awk simply processes the incoming data, without any check whether it found something there or not.
You set the task more correctly - what exactly are the values, an example of a file. Maybe you don't need awk
grep -oP "\s*\K.*(?=500)" /countCodes || echo "0"

Answer 2

echo "hhh" | awk '{ if (/iii/) { print $0 } else { print 0 } }'

Answer 3

in general
THE AWK LANGUAGE
1. Program structure
An AWK program is a sequence of pattern {action} pairs and user function definitions.
A pattern can be:
BEGIN
END
expression
expression , expression
i.e.
echo 'AB Z' | awk 'BEGIN{ status = 0} /ABC/ {status = 42 } END{ print "status=" status }
will give
status=0
and / a
echo 'AB C' | awk 'BEGIN{ status = 0} /AB C/ {status = 42 } END{ print "status=" status } '
will give
status=42