SQL和PHP批处理更新

Question

I have the following table with the following values :

                        id   name  farmid   amount    cycleid   totalprice  quantity  month     year
                        1    DAP     1      2400        1         24000      10       DECEMBER  2012
                        2    UREA    1      2500        1         5000        2       DECEMBER  2012
                        3    SENCOR  1      1200        1         2400        2       DECEMBER  2012
                        4    DAP     2      2400        1         2400        1       DECEMBER  2012
                        5    UREA    2      2500        1         2400        1       DECEMBER  2012
                        6    SENCOR  3      2000        2         4000        2       DECEMBER  2012
                        7    DAP     1      3000        2         3000        1       JANUARY   2013
                        8    UREA    2      3000        2         6000        2       JANUARY   2013
                        9    SENCOR  3      3000        2         6000        2       JANUARY   2013

I have a problem on formulating the right SQL statement to do a batch update for example Update rows with month of DECEMBER year of 2012 and only with farmid 1 NOTE: A farmid row cannot have more than one cycleid in the same month eg in the month of december. Please help to comeup with the right sql statement for the above problem.This is what I tried in code-igniter:

     $chemicalarray = array(
            1=>array('name'=>$B41,'farmid'=>$farmname_id,'amount'=>$D41,'cycleid'=>$cycleid,'totalprice'=>$E41,'quantity'=>$C41,'year'=>$E4,'month'=>$E5),
            2=>array('name'=>$B42,'farmid'=>$farmname_id,'amount'=>$D42,'cycleid'=>$cycleid,'totalprice'=>$E42,'quantity'=>$C42,'year'=>$E4,'month'=>$E5),
            3=>array('name'=>$B43,'farmid'=>$farmname_id,'amount'=>$D43,'cycleid'=>$cycleid,'totalprice'=>$E43,'quantity'=>$C43,'year'=>$E4,'month'=>$E5),
            4=>array('name'=>$B44,'farmid'=>$farmname_id,'amount'=>$D44,'cycleid'=>$cycleid,'totalprice'=>$E44,'quantity'=>$C44,'year'=>$E4,'month'=>$E5),
            5=>array('name'=>$B45,'farmid'=>$farmname_id,'amount'=>$D45,'cycleid'=>$cycleid,'totalprice'=>$E45,'quantity'=>$C45,'year'=>$E4,'month'=>$E5),
                              );
                    foreach ($chemicalarray as $key) {
                        $unitsql = "UPDATE chemical SET name = '{$key['name']}', farmid = '{$key['farmid']}' , 
                                        amount = '{$key['amount']}' , cycleid = '{$key['cycleid']}' , 
                                        totalprice = '{$key['totalprice']}', quantity = '{$key['quantity']}' 
                                    WHERE year = '{$key['year']}'
                                        AND month = '{$key['month']}'"; 
                        $q = mysql_query($unitsql); 
                        echo $key['name']; 
                        echo $key['amount']; 
                        if($q==true){ }else{ echo mysql_error(); }
                    }


Output of var_dump is :
array(8) { ["name"]=> string(8) "Round Up" ["farmid"]=> string(1) "1" ["amount"]=> float(1300) ["cycleid"]=> string(1) "1" ["totalprice"]=> float(15600) ["quantity"]=> float(12) ["year"]=> float(2012) ["month"]=> string(8) "DECEMBER" } Done11array(8) { ["name"]=> string(7) "Krismat" ["farmid"]=> string(1) "1" ["amount"]=> float(1500) ["cycleid"]=> string(1) "1" ["totalprice"]=> float(15000) ["quantity"]=> float(10) ["year"]=> float(2012) ["month"]=> string(8) "DECEMBER" } Done11array(8) { ["name"]=> string(3) "DAP" ["farmid"]=> string(1) "1" ["amount"]=> float(2500) ["cycleid"]=> string(1) "1" ["totalprice"]=> float(75000) ["quantity"]=> float(30) ["year"]=> float(2012) ["month"]=> string(8) "DECEMBER" } Done11array(8) { ["name"]=> string(4) "Urea" ["farmid"]=> string(1) "1" ["amount"]=> float(2000) ["cycleid"]=> string(1) "1" ["totalprice"]=> float(50000) ["quantity"]=> float(25) ["year"]=> float(2012) ["month"]=> string(8) "DECEMBER" } Done11array(8) { ["name"]=> string(9) "Dual Gold" ["farmid"]=> string(1) "1" ["amount"]=> float(2500) ["cycleid"]=> string(1) "1" ["totalprice"]=> float(75000) ["quantity"]=> float(30) ["year"]=> float(2012) ["month"]=> string(8) "DECEMBER" }

Answer 1

You are just updating the same exact rows over an over again for each month-year combination. If you need to limit the updates to only certain year - month - farmid combinations, then you need to add farmid in your WHERE clause.