按行数计算结果

Question

I'm trying to make a function which will display the top X results of the row Y which I set, for this instance I'm using the row browser and the top 5 results from my table statistics , the where is just to eliminate Search Bot results from showing up. I also want it to return the count of the amount of rows as well. So say there was 10 results for the browser 'Safari', then it would return the count of 10 for that result as well as the result itself.

$display->show_list('statistics', 'browser', '5', 'WHERE browser!=\'Search Bot\'');

Here is my function. I'm cleaned it up a bit to remove certain checks and outputs if the query were to fail, etc.

function show_list($table, $row, $limit = 5, $where = NULL) {

$item = mysql_query("SELECT DISTINCT $row FROM $table $where LIMIT $limit");

            $result = array();

while ($fetch = mysql_fetch_array($item)) {

            $result[] = $fetch;
}
            return $result;
}

Answer 1

Not sure I understand the question, but what about using a group by clause, in your SQL query :

select your_column, count(*)
from your_table
where ...
group by your_column
order by count(*) desc
limit 5

That would get you :

• for each value of your_column ,
• the number of rows with that value
• and you'd keep the 5 values of your_column that have the biggest number of rows

Answer 2

Change this line:

$item = mysql_query("SELECT $row, count(*) as rows FROM $table $where GROUP BY count(*) ORDER BY count(*) DESC LIMIT $limit");

After doing that, you may not want to mix this with your generic show_list function.

A random note. DISTINCT tends to be somewhat expensive on the database. I would avoid defaulting to doing it.

Incidentally your indentation is..interesting. No decent programmer will want to work with that code without reformatting to some consistent indentation scheme. There are endless arguments about the best way to format, but the following would be a reasonable indentation of your original code:

function show_list($table, $row, $limit = 5, $where = NULL) {

    $item = mysql_query("SELECT DISTINCT $row FROM $table $where LIMIT $limit");

    $result = array();

    while ($fetch = mysql_fetch_array($item)) {    
        $result[] = $fetch;
    }
    return $result;
}

Answer 3

function show_list($table, $column, $limit = 5, $where = '') {
    $item = mysql_query("SELECT $column, COUNT(*) AS c FROM $table $where
            GROUP BY $column ORDER BY c LIMIT $limit");
    $result = array();
    while ($fetch = mysql_fetch_array($item)) {
        $result[] = $fetch;
    }
    return $result;
}

• Replace row with column - we are actually passing a column name in the variable.
• Replace $where = null with $where = '' - it will ensure that the query works correctly even when $where is null .
• Modify the query to generate the expected results (to the best of my understanding of your question)
• Re-format the code and indent it properly.