Why Does My PDO Prepared Statement Fetch() Return Double Results?

PDO Prepared Statement Fetch() Returns Double Results

When using PDO prepared statements, the results obtained from the fetch() method can sometimes appear to be duplicated. This happens when the desired data is being retrieved twice per row, resulting in twice the expected number of columns in the output.

This issue occurs when fetching the data using the default PDO::FETCH_BOTH mode, which retrieves results indexed by both column name and column number. To prevent this duplication, specify an alternate fetch style, such as:

• PDO::FETCH_ASSOC: Returns an array indexed by column name, avoiding the duplication caused by the column number index.
• PDO::FETCH_NUM: Returns an array indexed by column number, eliminating the need for column name indexing.

By using either of these fetch modes, you can retrieve the correct number of columns for each row, ensuring that the output is displayed as intended.

Here's an example of how to use PDO::FETCH_ASSOC:

while ($rows_get_rows = $result_get_rows->fetch(PDO::FETCH_ASSOC)) {
    $csv .= '"' . join('","', str_replace('"', '""', $rows_get_rows)) . "\"\n";
}

This code will retrieve the data as an associative array, eliminating the duplicate columns.

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