MySQL有时会搜索null

Question

I have a slight issue with mySQL:

   if ($rooflightReportSalesReleaseFromDate !== "" ) {
       $sql .= "AND (date(orderRelease.Sales_Release_Date)) >= '" . $rooflightReportSalesReleaseFromDate
             . "' OR orderRelease.Sales_Release_Date IS NULL" ;
   }
   if ($rooflightReportSalesReleaseToDate !== "") {
       $sql .= " AND (date(orderRelease.Sales_Release_Date)) <= '" . $rooflightReportSalesReleaseToDate
       . "' OR orderRelease.Sales_Release_Date IS NULL";
   }

$rooflightReportSalesReleaseToDate and $rooflightReportSalesReleaseFromDate will sometimes be blank, but i'm fiding if both dates have values it's still returning null (probably because the OR statements). Is there a way i can get it to handle the null/blank records because i'm getting errors if i don't have the or statements in (or the null check is on its own)

Thanks.

Answer 1

You're mixing AND and OR so it is most likely an operator precedence issue. Just add parenthesis around OR operations:

if ($rooflightReportSalesReleaseFromDate !== "" ) {
    $sql .= "AND (
        date(orderRelease.Sales_Release_Date) >= '" . $rooflightReportSalesReleaseFromDate . "'
        OR orderRelease.Sales_Release_Date IS NULL
    )" ;
}
if ($rooflightReportSalesReleaseToDate !== "") {
    $sql .= " AND (
        date(orderRelease.Sales_Release_Date) <= '" . $rooflightReportSalesReleaseToDate . "'
        OR orderRelease.Sales_Release_Date IS NULL
    )";
}

Having said that, assuming that Sales_Release_Date contains date+time but the variables contain date only, you can eliminate the date() cast like so:

if ($rooflightReportSalesReleaseFromDate !== "" ) {
    $sql .= " AND (orderRelease.Sales_Release_Date >= '" . $rooflightReportSalesReleaseFromDate . "' OR orderRelease.Sales_Release_Date IS NULL)" ;
}
if ($rooflightReportSalesReleaseToDate !== "") {
    $sql .= " AND (orderRelease.Sales_Release_Date < '" . $rooflightReportSalesReleaseToDate . "' + INTERVAL 1 DAY OR orderRelease.Sales_Release_Date IS NULL)";
    // check for less than only -------------------^                                              ^
    // add one day to end date --------------------------------------------------------------------
}