WordPress search function to query database and work out distance between result

I’m working on a search function to find the difference between results, e.g. trying to find the result of best fit based on the input from a user form.

I will try to summarise my intentions for this:

User submits form of data and data is posted
The search-function.php script is fired
The search-function gets all of the relevant post_ids for the query
The search-function then works out the difference between the user input and the post’s values
The search-function will then return results order by the amount of difference they are from the user input.
Posts are a custom post type called product. I’m using advanced custom fields to create the custom fields (which is what the script it querying to work out the difference).

How would I correctly approach this script please?

Do you require any more info?

search-function.php

//get an array of post_ids for live products/drivers e.g.

$post_array = SELECT * post_id WHERE post_type = product AND post_status = publish FROM wp_posts

//select all of the custom fields that much the post_id from the array, then work out the distance from the user input, then return them according to distance

SELECT * WHERE post_id = $post_array, ABS($_POST[standard]-head_standard)+ABS($_POST[desired_shape]-shape)+ABS(($_POST[desired_height]*2)-(tracjectory_head_design+loft) as distance
FROM post_meta
ORDER BY distance ASC

form.php

<form action="search-function.php" class="" method="post" novalidate="">

        <div id="" class="content-area">
        <div id="content" class="site-content" role="main">
         <div id="" class="">
               <label for="standard">
                    What is your playing standard?
               </label>
               <select name="standard" required="required">
                    <option value="1">
                         Novice
                    </option>
                    <option value="2">
                         Standard
                    </option>
                    <option value="3">
                         Expert
                    </option>

               </select>
          </div>

          <div id="" class="">
               <label for="carry">
                    What is your carry distance?
               </label>
               <select name="carry" required="required">
                    <option value="1">
                         Up to 215
                    </option>
                    <option value="2">
                         230 - 270
                    </option>
                    <option value="3">
                         270+
                    </option>
               </select>
          </div>

          <div id="" class="">
               <label for="shape">
                    What is your natural shot shape
               </label>
               <select name="shape" required="required">
                    <option value="1">
                         Hook
                    </option>
                    <option value="2">
                         Draw
                    </option>
                    <option value="3">
                         Straight
                    </option>
                    <option value="4">
                         Fade
                    </option>
                    <option value="5">
                         Slice
                    </option>
               </select>
          </div>

          <div id="" class="">
               <label for="desired_shape">
                    What is your desired shot shape
               </label>
               <select name="desired_shape" required="required">
                    <option value="1">
                         Draw
                    </option>
                    <option value="2">
                         Straight
                    </option>
                    <option value="3">
                         Fade
                    </option>
               </select>
          </div>

          <div id="" class="">
               <label for="height">
                    What is your current ball height?
               </label>
               <select name="height" id="field5" required="required">
                    <option value="1">
                         Low
                    </option>
                    <option value="2">
                         Mid
                    </option>
                    <option value="3">
                         High
                    </option>
               </select>
          </div>

          <div id="" class="">
               <label for="desired_height">
                    What is your desired ball height?
               </label>
               <select name="desired_height" id="field6" required="required">
                    <option value="1">
                         Low
                    </option>
                    <option value="2">
                         Mid
                    </option>
                    <option value="3">
                         High
                    </option>
               </select>
          </div>

          <div id="" class="">
               <input type="submit" value="Submit">
          </div>
     </form>