如何使此UPDATE仅在while循环中起作用？

Question

I've been working on this for a couple days, and my brain has finally gone numb. My UPDATE is just updating every StartDate in the database, but I want it to only act on the event that is in the while loop this UPDATE is contained in. I think the code is probably fairly obvious, so here it is:

$query = "SELECT * FROM events WHERE ParentEventID='$tempParentEventID' AND GoogleID IS NULL";
$result = mysql_query($query);
            while($row = mysql_fetch_array($result, MYSQL_ASSOC)){

                $tempDaysFromEvent = $row['DaysFromEvent'];
                $tempStartDate = $row['StartDate'];

                //IF STARTDATE IS DIFFERENT FROM HOW IT USED TO BE, UPDATE IT.
                list($year, $month, $day) = explode("-", $tempStartDate);
                $tempStartDate      =   $tempEndDate    =    date("Y-m-d", mktime (0,0,0,$month,$day+$tempDaysFromEvent,$year));


                mysql_query("UPDATE".$eventDatabase." SET
                StartDate = '$tempStartDate'");


            }

I hope the above is clear enough. I am trying to change the StartDate in each $row as it goes through the loop.

Answer 1

如何添加where子句。

"UPDATE table SET field = '$sValue' WHERE eventID = ".$aRow['eventId']);

Answer 2

查询应该是

 "UPDATE".$eventDatabase." SET  StartDate = '$tempStartDate' WHERE EventId =". $row['evenID'];

Answer 3

simply add a WHERE -clause to your update-statement:

UPDATE table SET StartDate = ... WHERE [whatever*]

*you havn't posted you table definitions, but it sounds like you should use your event-id here.

Answer 4

您需要在UPDATE-Statement中使用WHERE- WHERE来标识要更新的行。