MYSQL to CSV - How to match column headings with selected columns - php

Question

Coming up empty on this one and could use some insight.
I'm try to select only certain column_names (not column data) to set as a header for CSV file.
Right now, I can only pull all of the column names with
$result = mysql_query("SHOW COLUMNS FROM ".$table);
The problem is that it pulls all of the column names and I'm only wanting certain columns' data. To get the data values this query is working perfectly:
$values = mysql_query("SELECT ".$columns." FROM ".$table." WHERE channel_id=26");
How do I select or show only the column names for the columns I list out in $columns, for example?
EDIT - I'm adding my full PHP here to provide more context. Line 7 is my problem.
<?php
$table = 'exp_channel_data'; // table we want to export
$columns = 'entry_id, field_id_26, field_id_27, '; // only the columns we want to show
$file = 'registrations-from-web'; // csv name.
$result = mysql_query("SHOW COLUMNS FROM ".$table);
$count = mysql_num_rows($result);
$csv_output = "";
if ($count > 0)
{
while ($row = mysql_fetch_assoc($result))
{
$csv_output .= $row['Field'].", ";
}
}
$csv_output .= "\n";
$values = mysql_query("SELECT ".$columns." FROM ".$table." WHERE channel_id=26");
while ($rowr = mysql_fetch_row($values))
{
for ($j=0; $j<$count; $j++)
{
$csv_output .= $rowr[$j].", ";
}
$csv_output .= "\n";
}
$filename = $file."_".date("d-m-Y_H-i",time());
header("Content-type: application/vnd.ms-excel");
header("Content-disposition: csv" . date("Y-m-d") . ".csv");
header( "Content-disposition: filename=".$filename.".csv");
print $csv_output;
exit;
?>

Answer 1

If you know the name of the columns, you can add them and/or print them directly from an array.
If you want to have access to the ones retrieved from the query anyway, you can $result = mysql_fetch_assoc($values); per row, and the keys will always contain the name of the columns since the resulting array is associative.
Try:
$values = mysql_query('SELECT '. $columns. ' FROM '.
$table. ' WHERE channel_id = 26');
print_r(mysql_fetch_assoc($values));
For an insight of the contents of the resulting array.
Now try:
$first = 1;
echo '<table>';
while ($assoc = mysql_fetch_assoc($values))
{
echo '<tr>';
if ($first)
{
foreach ($assoc as $key => $value)
echo "<th>$key</th>\n";
$first = 0;
}
else
{
foreach ($assoc as $key => $value)
echo "<td>$value</td>\n";
}
echo '</tr>';
}
echo '</table>';
If what you want is to print a CSV file:
$columns = Array();
$values = Array();
$first = 1;
for ($i = 0; $assoc = mysql_fetch_assoc($values); ++$i)
{
if ($first)
{
foreach ($assoc as $key => $value)
$columns[] = $key;
$first = 0;
}
else
{
foreach ($assoc as $key => $value)
$values[$i][] = $value;
}
}
$out = fopen('php://output', 'w');
fputcsv($out, $columns);
foreach ($values as $line)
fputcsv($out, $line);
The foreach is repeated on purpose so this example is more clear.

Answer 2

You can query the USER_TAB_COLUMNS table for table column metadata.
SELECT table_name, column_name, data_type, data_length
FROM USER_TAB_COLUMNS
WHERE table_name = 'yourTableName'

Answer 3

so you might be using SQL server - for SQL server use this...
SELECT [name] AS [Column Name]
FROM syscolumns
WHERE id = (SELECT id FROM sysobjects WHERE type = 'V' AND [Name] = 'Your table name')
Type = 'V' for views Type = 'U' for tables

Answer 4

I don't know why I was missing this, but since I'm already having to list out the columns I need, I just needed to turn that string into an array to make is it work.
$column_names = Array($columns);
then later use
$csv_output .= '"'.$rowr[$j].'",';
That worked perfectly without redoing my entire code.