If the command you referenced is working, modulo the variable issue, then this will probably do the trick:

Code:

str="no rows selected"
num=$(echo "$SQL_STRING" | awk -v str="$str" '{ n += gsub (str, "" ); } END{ print n+0; }')
echo $num

Depending on your needs, you could also just pipe the output of the database query command directly into awk and not worry about any size limits that the shell might put on the contents of a variable.

The 'n+0' in the print ensures that you get a number out. If the query returns no output, n will not have been set and the print will print a blank rather than 0; the n+0 forces it to print a zero.

---------- Post updated at 20:07 ---------- Previous update was at 19:39 ----------

As was pointed out in another post just a few minutes ago, if the SQL_STRING is empty, echo will still print a single newline so n should always be set. Caution never hurts though.