PHP过滤器合并为一个SQL查询

Question

I'm trying to filter through my database according to filters done by visitors.

$query = "select * from Sheet1 where";

//filter query start 
if (!empty($brand)) {
  $branddata = implode("','", $brand);
  //testing removing query
  $query .= " Brand in('$branddata') and";
}

if (!empty($model)) {
  $modeldata = implode("','", $model);
  //testing removing query
  $query .= " Model in('$modeldata') and";
}

/* if(!empty($model) && empty($brand)){

} */

if (!empty($spower) && !empty($epower)) {
  $query .= " Power>='$spower' and Power<='$epower' and";
}

if (!empty($sprice) && !empty($eprice)) {
  $query .= " Doors>='$sprice' and Doors<='$eprice'";
}

$rs = mysqli_query($conn, $query) or die("Error : " . mysqli_error($conn));

The result I wish to get is a sql query that works and has correct syntax. Such as select * from Sheet1 where Doors>='$sprice' and Doors<='$eprice' , if the visitor is filtering by price.

Currently, my code is made so that it simply adds a certain string to the variable. This means that if you don't filter by model, it skips model, because the model variable is empty. The problem comes to if you filter by power, the SQL will become select * from Sheet1 where Power>='$spower' and Power<='$epower' and . Obviously this doesn't work, so I need help in making the code make sure it works for every combination of filters.

Answer 1

I would do it this way

$filters=array();

if(!empty($brand)){
          $branddata =implode("','",$brand);
          //testing removing query
          $filters[]= " Brand in('$branddata')";
      }

if(!empty($model)){
          $modeldata =implode("','",$model);
          //testing removing query
          $filters[]= " Model in('$modeldata') and"; 
      }


  if(!empty($spower) && !empty($epower)){
          $filters[]= " Power>='$spower' and Power<='$epower' and"; 
      }

  if(!empty($sprice) && !empty($eprice)){
          $filters[]= " Doors>='$sprice' and Doors<='$eprice'"; 
      }

$query = "select * from Sheet1 where";  

foreach ($filters as $filter) {
$query.=' AND '.$filter;

}

 $rs = mysqli_query($conn,$query) or die("Error : ".mysqli_error($conn));

Answer 2

Append $query .= " 1 = 1"; at the end. I did some modification in your given code. Have a look.

<?php
$query = "SELECT * FROM `Sheet1` WHERE"; 

//filter query start 
if(!empty($brand)){
  $branddata = implode("','",$brand);
  $query  .= " (Brand in('$branddata')) AND";
}

if(!empty($model)){
  $modeldata = implode("','",$model);
  $query  .= " (Model in('$modeldata')) AND"; 
}

if(!empty($spower) && !empty($epower)){
  $query  .= " (Power>='$spower' AND Power<='$epower') AND"; 
}

if(!empty($sprice) && !empty($eprice)){
  $query  .= " (Doors>='$sprice' AND Doors<='$eprice') AND"; //Added 'AND'
}

$query .= " 1 = 1"; //Added new line

$rs = mysqli_query($conn,$query) or die("Error : ".mysqli_error($conn));
?>

Add AND on each query appended in if conditions. Then, at last add $query .= " 1 = 1"; . Which will save you from extra AND coming at the end. If none of the conditions satisfy, then your query will be SELECT * FROM Sheet1 WHERE 1 = 1 . Simple. And, don't forget to differentiate between conditions in query. Differentiate your conditions like how I did by opening and closing brackets.