PHP- MySQL 搜索条件

Question

我开发了一个包含多个字段的数据库——大约 65 个字段。我希望为我的用户提供多个搜索条件，即通过在下拉菜单中选择各种字段名称。我无法通过使用简单的 IF-ELSEIF-ELSE 语句来执行它。它只给出第一个 IF 语句的结果，而忽略其余的。

下面是html页面：

<form name="frm" action="search_plants.php" method="get">
            <table>
                <tr>
                    <td width="155" height="24">Select Scientific Name:</td>
      <td width="275">
                        <select name="spnm" size="1">       
                        <option value="0">  All</option>    
                        <option value="Abrus precatorius">  Abrus precatorius</option>  
                        <option value="Abutilon indicum">  Abutilon indicum</option>                    
                        <option value="Abutilon theophrasti"> Abutilon theophrasti</option>                 



                        </select>
                        </td>
              </tr>
                <tr>
                    <td>Select Family Name:</td>
                    <td>
                        <select name="fmnm" size="1">   
                        <option value="0">  All</option>
                        <option value="Fabaceae">Fabaceae</option>
                        <option value="Malvaceae">Malvaceae</option>
                        <option value="Mimosaceae">Mimosaceae</option>                      

                        </select>
                    </td>
                </tr>
                <tr>
                    <td>Select Geographic Location:</td>
                    <td>
                        <select name="znm" size="1">                    
                        <option value="0">  All</option>
                        <option value="North Gujarat">North Gujarat</option>
                        <option value="South Gujarat">South Gujarat</option>
                        <option value="South East Gujarat">South East Gujarat</option>      
                        <option value="Central Gujarat">Central Gujarat</option>
                        <option value="Kachchh">Kachchh</option>
                        <option value="Saurashtra">Saurashtra</option>

                        </select>
                    </td>
                </tr>
                <tr>
                <tr>
                    <td>Select Marker:</td>
                    <td>
                        <select name="pnm" size="1">                    
                        <option value="0">  All</option>
                        <option value="rbcL">rbcL</option>      
                        <option value="psbA-trnH">psbA-trnH</option>    
                        <option value="matK">matK</option>  
                        <option value="rpoC1">rpoC1</option>    
                        <option value="ITS2">ITS2</option>  
                        <option value="ycf5">ycf5</option>      

                        </select>
                    </td>
                </tr>
                <tr>
                    <td>
                        <input type="submit" value="Go" name="action">
                        <label>
                        <input type="reset" name="Reset" id="button" value="Reset">
                        </label>                        </td>
                </tr>
            </table>
        </form>

而表单动作页面如下，只描绘了整个编码的一部分。我想给用户一个选择任何/所有字段的选项，并能够通过从数据库中进行选择性搜索来显示它。请帮帮我。

if (($species == 0) || ($family == 0) || ($zones ==0 ) || ($marker == 0))   
    {
        if(($species==0) && ($family==0) && ($zones==0))
        {
            $sql="SELECT * FROM `ncbi_bold_ plants` WHERE Marker LIKE '$marker%'" ;
        }

        elseif($species==0 &&  $family==0 &&  $marker==0)
        {
        $sql="SELECT * FROM `ncbi_bold_ plants` WHERE Zones LIKE '%$zones%'";
        }

        elseif($family==0 &&  $zones==0 &&  $marker==0)
        {
        $sql="select * from `ncbi_bold_ plants` where Speciesname like '$species%'";

        }

        elseif($species==0 &&  $zones==0 &&  $marker==0)
        {
            $sql="select * from `ncbi_bold_ plants` where Family like '$family%'";

        }
    /*
    elseif($species==0 && $marker==0)
    {
        $sql="select * from `ncbi_bold_ plants` where Family like '$family%' AND Zones like '%$zones%'";
        $search_sql=mysql_query($sql) or trigger_error("There was an error.<br/>" . mysql_error() . "<br />SQL Was: {$sql}");
    }       
    elseif($family==0 && $zones==0 && $marker==0)
    {
        $sql="select * from `ncbi_bold_ plants` where Speciesname like '$species%'";
        $search_sql=mysql_query($sql) or trigger_error("There was an error.<br/>" . mysql_error() . "<br />SQL Was: {$sql}");
    }
    elseif($species==0 && $family==0)
    {
        $sql="select * from `ncbi_bold_ plants` where Zones like '%$zones%' AND marker like '$marker%'";
        $search_sql=mysql_query($sql) or trigger_error("There was an error.<br/>" . mysql_error() . "<br />SQL Was: {$sql}");
    }
    elseif($species==0 && $zones==0)
    {
        $sql="select * from `ncbi_bold_ plants` where Family like '$family%' AND marker like '$marker%'";
        $search_sql=mysql_query($sql) or trigger_error("There was an error.<br/>" . mysql_error() . "<br />SQL Was: {$sql}");
    }
    elseif($species==0 && $marker==0)
    {
        $sql="select * from `ncbi_bold_ plants` where Family like '$family%' AND Zones like '%$zones%'";
        $search_sql=mysql_query($sql) or trigger_error("There was an error.<br/>" . mysql_error() . "<br />SQL Was: {$sql}");
    }
    */          
        else
        {
        $sql="SELECT * FROM `ncbi_bold_ plants` " ;
        }

    }

    else 
    {
        $sql="select * from `ncbi_bold_ plants` where Speciesname like '$species%' and Family like '$family%' and Zones like '%$zones%' and Marker like '$marker%'";


    }

    $search_sql=mysql_query($sql) or trigger_error("There was an error.<br/>" . mysql_error() . "<br />SQL Was: {$sql}");

请帮助我。我在 if 语句中找不到缺陷。

Answer 1

试试这个简单的功能：

function create_query($p_species, $p_family, $p_zones, $p_marker) {
  $options = array(
    'Speciesname' => $p_species,
    'Family' => $p_family,
    'Zones' => $p_zones,
    'Marker' => $p_marker
    );
  $cond = '';
  $noopt = true;
  foreach ($options as $column => $value) {
    if ($value !== 0) {
      $noopt = false;
      if ($cond != '') $cond .= ' AND ';
      $cond .= "$column LIKE '%$value%'";
      }
    }
  return $noopt ? false : "SELECT * FROM ncbi_bold_ plants WHERE $cond;";
  }

如果所有参数都为零，此函数返回false，否则返回查询字符串。

示例 #1：

$species = 'spectest';
$family = 0;
$zones = 'zonestest';
$marker = 0;

echo create_query($species, $family, $zones, $marker);

输出：

SELECT * FROM ncbi_bold_ plants WHERE Speciesname LIKE '%spectest%' AND Zones LIKE '%zonestest%';

示例 #2：

$species = 0;
$family = 0;
$zones = 0;
$marker = 0;

var_dump(create_query($species, $family, $zones, $marker));

输出：

bool(false)

或者，如果您想返回不带条件的查询字符串而不是 false，只需将函数中的 return 行替换为：

return $noopt ? "SELECT * FROM ncbi_bold_ plants;" : "SELECT * FROM ncbi_bold_ plants WHERE $cond;";

---

现在，如果您想使用大量 IF、ELSEIF 和 ELSE 语句以您的方式执行此操作，则有以下解决方案：

没有功能的解决方案

（它的工作方式与上面的函数相同）：

  if ($species == 0 && $family == 0 && $zones == 0 && $marker == 0) {
    $sql = "SELECT * FROM ncbi_bold_plants";
    }
  elseif ($species == 0 && $family == 0 && $zones == 0) {
    $sql = "SELECT * FROM ncbi_bold_plants WHERE Marker LIKE '$marker%'";
    }
  elseif ($species == 0 && $family == 0 && $marker == 0) {
    $sql = "SELECT * FROM ncbi_bold_plants WHERE Zones LIKE '$zones%'";
    }
  elseif ($species == 0 && $zones == 0 && $marker == 0) {
    $sql = "SELECT * FROM ncbi_bold_plants WHERE Family LIKE '$family%'";
    }
  elseif ($family == 0 && $zones == 0 && $marker == 0) {
    $sql = "SELECT * FROM ncbi_bold_plants WHERE Speciesname LIKE '$species%'";
    }
  elseif ($species == 0 && $family == 0) {
    $sql = "SELECT * FROM ncbi_bold_plants WHERE Zones LIKE '$zones%' AND Marker LIKE '$marker%'";
    }
  elseif ($species == 0 && $zones == 0) {
    $sql = "SELECT * FROM ncbi_bold_plants WHERE Family LIKE '$family%' AND Marker LIKE '$marker%'";
    }
  elseif ($species == 0 && $marker == 0) {
    $sql = "SELECT * FROM ncbi_bold_plants WHERE Family LIKE '$family%' AND Zones LIKE '$zones%'";
    }
  elseif ($family == 0 && $zones == 0) {
    $sql = "SELECT * FROM ncbi_bold_plants WHERE Speciesname LIKE '$species%' AND Marker LIKE '$marker%'";
    }
  elseif ($family == 0 && $marker == 0) {
    $sql = "SELECT * FROM ncbi_bold_plants WHERE Speciesname LIKE '$species%' AND Zones LIKE '$zones%'";
    }
  elseif ($zones == 0 && $marker == 0) {
    $sql = "SELECT * FROM ncbi_bold_plants WHERE Speciesname LIKE '$species%' AND Family LIKE '$family%'";
    }
  elseif ($species == 0) {
    $sql = "SELECT * FROM ncbi_bold_plants WHERE Family LIKE '$family%' AND Zones LIKE '$zones%' AND Marker LIKE '$marker%'";
    }
  elseif ($family == 0) {
    $sql = "SELECT * FROM ncbi_bold_plants WHERE Speciesname LIKE '$species%' AND Zones LIKE '$zones%' AND Marker LIKE '$marker%'";
    }
  elseif ($zones == 0) {
    $sql = "SELECT * FROM ncbi_bold_plants WHERE Speciesname LIKE '$species%' AND Family LIKE '$family%' AND Marker LIKE '$marker%'";
    }
  elseif ($marker == 0) {
    $sql = "SELECT * FROM ncbi_bold_plants WHERE Speciesname LIKE '$species%' AND Family LIKE '$family%' AND Zones LIKE '$zones%'";
    }
  else {
    $sql = "SELECT * FROM ncbi_bold_plants WHERE Speciesname LIKE '$species%' AND Family LIKE '$family%' AND Zones LIKE '$zones%' AND Marker LIKE '$marker%'";
    }

  // here you have your $sql ... now do whatever you want with your query
  echo $sql;

此代码已针对所有可能的情况进行了测试，因此如果仍然无法正常工作，则说明您的问题不在您上面发布的 PHP 示例中。我不推荐这种方式，因为这是完全错误的方法，即使对于初学者也是如此。

如果您仍想使用 IF/ELSE/ELSEIF 进行设置，请考虑条件检查 IF 变量不等于零。你会得到更少的代码和更容易的实现。像这样的：

不同的方法

$species = 0;
$family = 0;
$zones = 0;
$marker = 0;

// default query w/out conditions
$sql = "SELECT * FROM ncbi_bold_plants";

// conditions array
$conditions = array();

// adding condition to array for every parameter <> 0
if ($species != 0) $conditions[] = "Speciesname LIKE '$species%'";
if ($family != 0) $conditions[] = "Family LIKE '$family%'";
if ($zones != 0) $conditions[] = "Zones LIKE '$zones%'";
if ($marker != 0) $conditions[] = "Marker LIKE '$marker%'";

// all we need now is to concatenate array elements with " AND " glue
$sql_cond = join(" AND ", $conditions);

// last thing, adding condition(s) to the main query (if there's any)
if ($sql_cond != '') $sql .= " WHERE $sql_cond";

// let see what we have now
echo $sql;

前 4 行仅用于测试。现在，我们的解决方案与之前的解决方案相同，但代码更少（仅 8 行）。

希望这会有所帮助。

Answer 2

为什么不从字段中创建动态下拉菜单？例如。 （我在我自己的页面上使用它，您必须相应地编辑 SQL 语法/查询

echo "\n\t<select name='cat'>";
echo "\n\t\t<option value=''>Search all...</option>";
$connect = mysql_connect( <connection settings> );
$ctgTableCmd = "SELECT name FROM offliner.ctgtable ORDER BY name ASC";
$getCtg = mysql_query( $ctgTableCmd );
while( $ctgTable = mysql_fetch_array( $getCtg ) )
{
    $ctgVal = $ctgTable[0];
    echo "\n\t\t<option value=$ctgTable[0]>" . ucfirst( $ctgTable[0] ) . "</option>";
}

Answer 3

try using following approach

if($species)
{
  $colum='Species';
  $val=$family;
}
else
if($family)
{
  $colum='Family';
  $val=$family;
}
else
if($zones)
{
  $colum='Zones';
  $val=$zones;
}
else
if($marker)
{
  $colum='Marker';
  $val=$marker;
}
else
{
$column='';
$val='';

}

$sql="SELECT * FROM `ncbi_bold_ plants` WHERE $column LIKE '%".$val."%'" ;

Answer 4

你可以这样做。首先为自己定制：

<?php
$where = '';
if(isset($_POST))
{
    foreach($_POST as $k=>$v)
    {
        $q[] = $k.' LIKE \'%'.$v.'%\'';
    }
    $where = implode(' AND ',$q);
}
if(!empty($where))
    $sql = 'SELECT * FROM `ncbi_bold_ plants` WHERE '.$where;
else
    $sql = 'SELECT * FROM `ncbi_bold_ plants`"; 
    ......
    ......