SQL / MySQL SERVER – Count Duplicate Records – Rows


In my previous article SQL SERVER – Delete Duplicate Records – Rows, we have seen how we can delete all the duplicate records in one simple query. In this article we will see how to find count of all the duplicate records in the table. Following query demonstrates usage of GROUP BY, HAVING, ORDER BY in one query and returns the results with duplicate column and its count in descending order.

SELECT YourColumnCOUNT(*) TotalCount
FROM YourTable
GROUP BY YourColumn
HAVING COUNT(*) > 1
ORDER BY COUNT(*) DESC


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Export to CSV file and download – PHP


function CSVExport() {
$query=”SELECT id,email FROM `newsletterusers` WHERE `status` = 1”;
$sql_csv = mysql_query($query) or die(“Error: ” . mysql_error()); //Replace this line with what is appropriate for your DB abstraction layer

header(“Content-type:text/octect-stream”);
header(“Content-Disposition:attachment;filename=newsletterusers.csv”);
while($row = mysql_fetch_row($sql_csv)) {
print ‘”’ . stripslashes(implode(‘”,”’,$row)) . “"n”;
}
exit;
}