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。它只给出了第一个IF语句的结果，而忽略了其余的语句。
以下是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>
表单操作页面如下所示，仅描绘整个编码的一部分。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: {$sql}");
请帮我一样。我无法在if语句中找到缺陷。
答案 0 :(得分：3)
function create_query($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，则此函数返回 false ，否则返回查询字符串。
$species = 'spectest';
$family = 0;
$zones = 'zonestest';
$marker = 0;
echo create_query($species, $family, $zones, $marker);
<强>输出：
SELECT * FROM ncbi_bold_ plants WHERE Speciesname LIKE '%spectest%' AND Zones LIKE '%zonestest%';
$species = 0;
$family = 0;
$zones = 0;
$marker = 0;
var_dump(create_query($species, $family, $zones, $marker));
<强>输出：
bool(false)
或者，如果您想在没有条件的情况下返回查询字符串而不是 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 $cond;";
<小时/> 现在，如果你想用大量的IF，ELSEIF和ELSE语句来做这个，那就有解决方案：
（它的工作方式与上面的功能相同）：
if ($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，因此如果它仍然不起作用，则问题不在上面发布的PHP示例中。我不建议这种方式，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，请考虑条件检查IF变量是否等于零。您将获得更少的代码和更容易的实现。像这样：
$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，我们有与之前相同的解决方案，但代码较少（仅限8行）。
希望这会有所帮助。
答案 1 :(得分：1)
为什么不从字段创建动态下拉菜单？例如。 （我在自己的页面上使用它，你必须相应地编辑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>";
}
答案 2 :(得分：0)
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
$sql = 'SELECT * FROM `ncbi_bold_ plants`";
......
......
答案 3 :(得分：0)
try using following approach
if($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."%'" ;