PHP在字符串中的字符串中变量

I am attempting to echo a sting containing a variable already stored in a variable. Essentially I am building a class that can dynamically build tables based on a changing number of columns. I need get my db field names into the foreach loop before the foreach loop that has my db results, and then iterate over them in the loop. The problem is I have to store them in a loop prior to the db results loop; which is not recognizing it as a variable and just giving me a plain text '$row['myVar']'.

How can I get this to recognize the variable in the second loop?

$sqlVarNames = explode(', ', $sqlVar);
foreach ($sqlVarNames as $columnVar) {
    $finalColumnVars .= '<td>\'. $row[\''.$columnVar.'\'] .\'</td>';
}

and then into my second loop

foreach ($sqlResult as $row) {
    echo '<tr>';
    echo $finalColumnVars;
    echo '</tr>';
} 

I tried all sorts of escape sequences on my $finalColumnVars and can't seem to get it to output the variable instead on plain text.

Here is what I get with the above code

<td>'. $row['client_name'] .'</td>

Is this possible?

here is how you can merge these two loop and get the desired.

$sqlVarNames = explode(', ', $sqlVar);
foreach ($sqlResult as $row) {
    echo '<tr>';
    foreach ($sqlVarNames as $columnVar) {
        echo '<td>'. $row[$columnVar] .'</td>';
    }
    echo '</tr>';
} 

$sqlVarNames = explode(', ', $sqlVar);
foreach ($sqlVarNames as $columnVar) {
    $finalColumnVars .= '<td>'.$row[$columnVar].'</td>';
}