在第4行'ORDER BY date DESC LIMIT 1'附近使用的正确语法[关闭]

Question

I keep getting the following error:

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'ORDER BY date DESC LIMIT 1' at line 4

function printSoldiersOfRank($rank, $branch)
{
  $soldier = new soldierClass;
  $sql = "SELECT * FROM soldier WHERE rank = $rank AND branch = '$branch'";
  $result = mysql_query($sql);
  while($row = mysql_fetch_array($result)):
    $soldier->getInfo($row['sID']);
    $soldier->printInfo(); 
  endwhile;

function printInfo()
  {
    $sql = "SELECT promoter, name, date
    FROM soldier s, log l
    WHERE s.sID = l.promoter AND l.promotee = $this->sid
    ORDER BY date DESC LIMIT 1";
    $result = mysql_query($sql) or die(mysql_error());
    $row = mysql_fetch_array($result);
    echo "<div class='soldierInfo'>";
    echo "<a href='index.php?page=soldier&sid=$this->sid'>";
    echo $this->name;
    echo "</a><br />";
    echo "Last Promoted: ";
    echo date("d M Y", $row['date']);
    echo "<br />By: <a href='index.php?page=soldier&sid=$row[0]'>";
    echo $row['name'];
    echo "</a></div>";
  }

I'm assuming the error is in my printInfo() function. All help is appreciated, thanks in advance.

Answer 1

Don't assume that the error is anywhere. Instead create an error message that gives you all the information you need to debug. Here is an example.

$sql = 
"
SELECT promoter, name, date
FROM soldier s, log l
WHERE ( s.sID = l.promoter AND l.promotee = $this->sid )
ORDER BY date DESC 
LIMIT 1
"
;

$result = mysql_query($sql);
if (!$result)
{
    echo PHP_EOL;
    echo "<br/>";
    echo "FAILED QUERY $sql";
    echo "<br/> ON ";
    echo __LINE__;
    echo " IN ";
    echo __FILE__;
    echo "<br/>";
    echo " BECAUSE ";
    die(mysql_error());
}

If you use something like that, you will be able to see the query that failed and the location of the failure with certainty. As it stands now, you have a query that uses "ORDER BY date DESC" and an error message that says "ORDER BY name ASC" so it leaves me to wonder if we are looking at the right script!