Use for loop to incrementally select values from MySQL query - php

Question

I am trying to use a for loop to select an incremental value with a MySQL query. I have included sample code below:
<?php
$day_1="sep_28";
$day_2="sep_29";
$day_3="sep_30";
$query = mysql_query("SELECT * FROM table WHERE id = '$id'");
while ($row = mysql_fetch_assoc($query))
{
for ($i = 1; $i <= 3; $i++)
{
$dayVar = "day_".$i;
//$dayVarCount = $dayVar."_count"; // Don't really need this anymore, so removed.
$dayVarCount = $row[$$dayVar];
echo "$$dayVar.': '.$dayVarCount<p>"; // Edited.
}
}
?>
I think I am getting close, but when I run the code my page is showing this:
$day_1.': '.0
$day_2.': '.2
$day_3.': '.5
Any additional recommendations? Thanks for the great help!

Answer 1

Try a variable variable:
for ($i = 1; $i <= 3; $i++)
{
$dayVar = "day_".$i;
$dayVarCount = $dayVar."_count";
$$dayVarCount = $row[$$dayVar];
echo $$dayVar.': '.$$dayVarCount.'<p>'; // Edited.
}
This basically uses a string to reference a variable by its name.
Just think of it this way:
$variable = 'hello';
$string = 'variable';
echo $$string;
// Is the same thing as:
echo $variable;
// Because you can thing of $$string as ${$string} ---> $variable when {$string} is interpreted into 'variable'
http://php.net/manual/en/language.variables.variable.php

Answer 2

Replace this line:
echo "$$dayVar.': '.$dayVarCount<p>";
with this:
echo $$dayVar . ': ' . $dayVarCount . '<br>';

Answer 3

<?php
$day_1="January 1";
$day_2="January 2";
$day_3="January 3";
$query = mysql_query("SELECT * FROM dates WHERE id = '$id'");
while ($row = mysql_fetch_assoc($query))
{
for ($i = 1; $i <= 3; $i++)
{
$var = $."day_".$i;
$day_$i_count=$row['$var'];
echo "$day_$i: $day_$i_count<p>";
}
}
?>
You can try this code too.

Answer 4

That all seems overly complicated, but possibly I don't understand the question adequately. Would this work?
$day[1]="sep_28";
$day[2]="sep_29";
$day[3]="sep_30";
$query = mysql_query("SELECT * FROM table WHERE id = '$id'");
while ($row = mysql_fetch_assoc($query))
{
foreach ($day as $day_str)
{
echo $day_str . ':' . $row[$day_str] . '<p>';
}
}