Combination of field search using PHP & MYSQL

问题

I am working on an assignment using PHP & MYSQL.

one of the tasks is to search on any combination of the fields. That includes Dropdown boxes populated from the Database. and Text fields.

t2ath contains

ID
SPORT
COUNTRY
GENDER
FIRSTNAME
LASTNAME
Image

I've been working on this code for a week to be able to search on any combination with no errors.

I am wondering if there is another more efficient way to do it.

$selectedSport = $_POST['sport']; $gender =$_POST['gender']; $fName =$_POST['fname']; $lName =$_POST['lname']; $country =$_POST['country'];
$sql_fName=""; $sql_lName=""; $sql_gender=""; $sql_sport=""; $sql_country="";
$checkFiled=False;
$where="";
$and="";
//
if ( $selectedSport=="showAll")
    {
        !isset($selectedSport);
    }
else
    {
        if (isset($selectedSport)) 
            { 
                if ($checkFiled==True)
                    {

                        $sql_sport = " AND t2ath.sport = '$selectedSport'" ; 

                    }
                else
                    {
                        $sql_sport = " t2ath.sport = '$selectedSport' " ; 
                        $checkFiled=True;   
                    } 
            }
        else {
            $sql_sport = "";  
        }
    }

//
if ( $country =="showAll")
    {
        !isset($country);
    }
else
    {
        if (isset($country)) 
            { 
                if ($checkFiled ==True)
                    {

                        $sql_country = " AND t2ath.country = '$country'" ; 

                    }
                else
                    {
                        $sql_country = " t2ath.country = '$country' " ; 
                        $checkFiled=True;
                    } 
            }
        else {
            $sql_country = "";  
        }
    }
//
if ( $gender=="Gender")
    {
        !isset($gender);
    }
else
    {
        if (isset($gender)) 
            { 
                if ($checkFiled ==True)
                    {

                        $sql_gender = " AND t2ath.gender = '$gender'" ; 

                    }
                else
                    {
                        $sql_gender = " t2ath.gender = '$gender' " ; 
                        $checkFiled=True;
                    } 
            }
        else {
            $sql_gender = "";  
        }
    }
//
if ($fName =="")
    {
        !isset($fName);
    }
else
    {
        if (isset($fName)) 
            { 
                if ($checkFiled==True)
                    {

                        $sql_fName = " AND t2ath.firstName = '$fName'" ; 
                    }
                else
                    {
                        $sql_fName = " t2ath.firstName = '$fName' " ; 
                        $checkFiled=True;   
                    } 
            }
        else {
            $sql_fName = "";  
        }
    }
//
if ($lName =="")
    {
        !isset($lName);
    }
else
    {
        if (isset($lName)) 
            { 
                if ($checkFiled==True)
                    {

                        $sql_lName = " AND t2ath.lastName = '$lName' " ; 

                    } 
                else
                    {
                        $sql_lName = " t2ath.lastName = '$lName' " ; 
                        $checkFiled=True;
                    }
            }
        else
            {
                $sql_lName = "";  
            }
    }

if ($checkFiled == True)
    $where=" where ";

$selectString = "SELECT t2ath.lastName,t2ath.firstName,t2ath.image,t2ath.sport,t2ath.gender,t2ath.country,t2country.flag FROM t2ath LEFT JOIN t2country
                 ON t2ath.country = t2country.name $where  $sql_sport   $sql_country $sql_gender $sql_fName $sql_lName  ";
$result = mysql_query($selectString);

回答1:

Instead of all those conditionals about whether to add AND when concatenating to the query, use an array and implode.

$fields = array('sport' => 'sport',
                'gender' => 'gender', 
                'fname' => 'firstName',
                'lname' => 'lastName',
                'country' => 'country');
$wheres = array();
foreach ($fields as $postfield => $dbfield) {
    if ($_POST[$postfield] != 'showAll') {
        $wheres[] = "$dbfield = '" . mysql_real_escape_string($_POST[$postfield]) . "'";
    }
}
$selectString = "SELECT t2ath.lastName, t2ath.firstName, t2ath.image, t2ath.sport, t2ath.gender, t2ath.country, t2country.flag 
                 FROM t2ath LEFT JOIN t2country
                 ON t2ath.country = t2country.name";
if (count($wheres) > 0) {
    $selectString .= " WHERE " . implode(" AND ", $wheres);
}
$result = mysql_query($selectString);

To see how to do it similarly using PDO prepared statements, see my answer here: What code approach would let users apply three optional variables in PHP/MySQL?

回答2:

I've done something similar in the past where I checked the value from different fields and then added them to a series of arrays. I created an array for select, from, where, order. You can do similar for other sets like group or limit. Then I ran 'array_unique', imploded them and put them into the SQL string.

$array_select = array('users.Id'); // SET SOME DEFAULTS SO THE QUERY WILL ALWAYS RUN
$array_from = array('users');
$array_where = array();
$array_order = array();

if (isset($first_name)) {
    $array_select[] = 'First_Name';
    $array_from[] = 'users';
}

if (isset($city)) {
    $array_select[] = 'City';
    $array_from[] = 'user_contact';
    $array_where[] = 'users.Id = user_contact.City';
}

if ($array_select) {
    $array_select = array_unique($array_select);
    $string_select = implode(', ', $array_select);
}
if ($array_where) {
    $array_where = array_unique($array_where);
    $string_where = 'WHERE '.implode(' AND ', $array_where);
}
// REPEAT FOR OTHERS ...



// BUILD THE QUERY OUT
$sql = 'SELECT '.$string_select.' FROM '.$string_from.' '.$string_where.' ...

回答3:

Why not evaluate your string with each column (this is a guide only, I'm not building your PHP code there:

SELECT 
  * 
FROM 
  table
WHERE 
  (ID = $id OR $id = 'showAll')
  AND (SPORT = $sport OR $sport = 'showAll')
  AND (COUNTRY = $country OR $country = 'showAll')
  AND (GENDER = $gender OR $gender = 'showAll')
  AND (FIRSTNAME = $firstname OR $firstname = 'showAll')

Just need to make sure you NVL the variables to an appropriate value (whether it be int or string)

来源：https://stackoverflow.com/questions/21691675/combination-of-field-search-using-php-mysql