SELECT Statement Return Zero

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This statement returns the correct numbers, but when there are no results I need it to return '0'...I tried the standard way to do it but it doesn't debug. Right now it just shows a blank when a record isn't returned. This is a console app.

mysql_query(conn,"SELECT * FROM tblURL WHERE IP = '192.168.1.1','0'");
		my_ulonglong i = 0;
		res_set = mysql_store_result(conn);
		my_ulonglong numrows = mysql_num_rows(res_set);
		while ((row = mysql_fetch_row(res_set)) != NULL){
		printf("%s\n",row[i] != NULL ?
        row[i] : "NULL");

[edit]Code block added, inline code removed - OriginalGriff[/edit]

Posted 11-May-11 5:31am

Member 7766180

Updated 11-May-11 5:33am

OriginalGriff

v2

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3 solutions

Solution 3

Like OriginalGriff said, it is much easier to test numrows for zero than to write a complicated sql to return 0. Rememeber you are doing select *, which means your return will have a bunch of fields (possibly) or in the case of 0 single field. It is much easier to check for returned rows.

Posted 11-May-11 6:00am

Yusuf

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Member 7766180 11-May-11 12:33pm

Correct

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OriginalGriff · Accepted Answer · 2011-05-11T05:35:00

Solution 1

Why don't you just test "numrows" and see if that is zero?

Posted 11-May-11 5:35am

OriginalGriff

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Member 7766180 11-May-11 12:22pm

Could I see an example? Please?
DS

Member 7766180 11-May-11 12:29pm

I'm sorry, I think Kim posted an example. My bag of chips was in the way! LOL!!!

Kim Togo · Accepted Answer · 2011-05-11T05:53:00

Use "SELECT COUNT(*) FROM tblURL WHERE IP = '192.168.1.1'". It will ALWAY return 1 row and 1 column where the count is.

via mysql command prompt:

mysql> SELECT COUNT(*) FROM tblURL WHERE IP = '192.168.1.1';
+----------+
| COUNT(*) |
+----------+
| 9 |
+----------+

If there is 9 rows where IP is '192.168.1.1'. If there is 0 (zero) result will be.

mysql> SELECT COUNT(*) FROM tblURL WHERE IP = '80.66.44.22';
+----------+
| COUNT(*) |
+----------+
| 0 |
+----------+

mysql_query(conn,"SELECT COUNT(*) FROM tblURL WHERE IP = '192.168.1.1'");
res_set = mysql_store_result(conn);
my_ulonglong numrows = mysql_num_rows(res_set);

if (numrows > 0)
{
  row = mysql_fetch_row(res_set));
  printf("Count is: %s\n",row[0]);
}