Match Where Multiple Columns are... PHP PDO - php

Question

I have a search query which works, but not the way I had hope. Here:
try{
/*
Create Search Query.
*/
//Include database config file.
include('config.php');
//Get values from Angular.
$valuesPost=$_POST;
$values=array();
foreach ($valuesPost as $rows) {
$decodedValues=json_decode($rows, TRUE);
$values[]=$decodedValues;
}
//Get table from post values.
$table=$values[0]["table"];
//Get limit from post values.
$limit=$values[0]["limit"];
//Get offset from post values.
$offset=$values[0]["offset"];
//Get orderBy from post values.
$orderBy=$values[0]["orderBy"];
//Unset Whole array
unset($values[0]);
//Create cats fields
$cats=array_keys($values[1]);
if(empty($cats)) {
$cats = null;
} else {
foreach($cats as &$val){
$val="cat_id = :".$val;
}
$cats=implode(" OR ", $cats);
}
//Create subCats fields
$subCats=array_keys($values[2]);
if(empty($values[2])) {
$subCats[0] = null;
} else {
foreach($subCats as &$val){
$val="sub_cat_id = :".$val;
}
$subCats=implode(" OR ", $subCats);
}
//Create colourCats fields
$colourCats=array_keys($values[3]);
if(empty($colourCats)) {
$colourCats[0] = null;
} else {
foreach($colourCats as &$val){
$val="colour_id = :".$val;
}
$colourCats=implode(" OR ", $colourCats);
}
$where = "";
//Create Where Statement
if(empty($cats[0]) && empty($subCats[0])){
$where = $colourCats;
}
if(empty($cats[0]) && empty($colourCats[0])){
$where = $subCats;
}
if(empty($subCats[0]) && empty($colourCats[0])){
$where = $cats;
}
if(empty($colourCats[0]) && !empty($cats[0]) && !empty($subCats[0])){
$where = $cats." AND ".$subCats;
}
if(empty($subCats[0]) && !empty($cats[0]) && !empty($colourCats[0])){
$where = $cats." AND ".$colourCats;
}
if(empty($cats[0]) && !empty($subCats[0]) && !empty($colourCats[0])){
$where = $subCats." AND ".$colourCats;
}
if(!empty($cats[0]) && !empty($subCats[0]) && !empty($colourCats[0])){
$where = $cats." AND ".$subCats." AND ".$colourCats;
}
//Search query.
$search="SELECT * FROM $table WHERE $where ORDER BY $orderBy LIMIT $limit OFFSET $offset";
/*
Database Connection.
*/
//Crate a database connection variable: $conn and error checking attributes.
$conn = new PDO($DB_SETTINGS, $DB_USER, $DB_PASS);
$conn->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );
/*
PDO WORK.
*/
//SEARCH_LIKE_ALL QUERY!
//Prepare query.
$search_qry=$conn->prepare($search);
//For each array index create array $rows.
foreach ($values as $rows) {
//Bind each value to $value_fields from $rows array.
foreach ($rows as $key => &$value) {
switch(gettype($value)) {
case 'integer':
case 'double':
$search_qry->bindParam(':' . $key, $value, PDO::PARAM_INT);
break;
default:
$search_qry->bindParam(':' . $key, $value, PDO::PARAM_STR);
}
}
}
$search_qry->execute();
$rows = $search_qry->fetchAll(PDO::FETCH_ASSOC);
echo json_encode($rows);
} catch(PDOException $e) {
echo 'ERROR: ' . $e->getMessage();
}
It builds the query fine. In my angularjs script I build a multidimensional array where index [0] contains data such as table, orderby and limits. Index [1] contains an array of Categories. Index[2] an array of Sub Categories and Index[3] an array of Colour Categories. My problem is that the search query is bring back data I am not expecting. So lets say I send this type of array:
values[0]={table: table, order_by: prod_code, limit: 10, offset 0}
values[1]={cat_id0: 1};
values[2]={sub_cat_id0: 1, sub_cat_id1: 3}
values[3]={colour_id0: 1, colour_id1: 2}
I want only products in cat 1 with sub cats 2 & 3 and a colour id 1 & 2. It is changing order when I remove a sub cat id from the array but is still in search, I assume this product is later being picked up by a colour id. Is the query wrong or the way in which I am searching.
From the array above:
$search="SELECT * FROM table WHERE cat_id=:cat_id0 AND sub_cat_id=:sub_cat_id0 OR sub_cat_id=:sub_cat_id1 AND colour_id=:colour_id0 OR colour_id=:colour_id1 ORDER BY prod_code LIMIT 10 OFFSET 0"

Answer 1

I think the big problem you have is the order of precedence between AND and OR.
SELECT a
, b
, c
, a OR b AND c
, (a OR b) AND c
FROM ( SELECT 1 AS a UNION SELECT 0 ) a
CROSS
JOIN ( SELECT 1 AS b UNION SELECT 0 ) b
CROSS
JOIN ( SELECT 1 AS c UNION SELECT 0 ) c
WHERE NOT (a.a = b.b AND a.a = c.c)
ORDER BY c, b, a
a b c a OR b AND c (a OR b) AND c
------ ------ ------ ------------ --------------
1 0 0 1 0
0 1 0 0 0
1 1 0 1 0
0 0 1 0 0
1 0 1 1 1
0 1 1 1 1
That is to say
foo = a OR foo = b AND bar = c
is evaluated as:
( foo = a ) OR ( foo = b AND bar = c )
when what you probably want is:
(foo = a OR foo = b ) AND ( bar = c )
I'm having trouble deciphering what the code is doing.
For example, why do you need all those permutations of conditions in building the WHERE clause? Why all those checks? Why not something simpler, like:
$where = " 1=1";
if (!empty($cats[0]) {
$where .= " AND (" . $cats . ")";
}
if (!empty($subCats[0]) {
$where .= " AND (" . $subCats . ")";
}
if (!empty($colourCats[0]) {
$where .= " AND (" . $colourCats . ")";
}
Also, all those OR conditions testing equality
foo = a OR foo = b OR foo = c OR foo = d
Can be expressed much more elegantly using an IN
foo IN (a,b,c,d)
//Create cats fields
$cats=array_keys($values[1]);
if(empty($cats)) {
$cats = null;
} else {
$cats=" cat_id IN (". implode(",",$cats) . ");
}