Question

Hello there I have a database that has 2 tables in it, one is the categoryTable and the is the userMenuTable, the categoryTable currently has two columns in it, categoryId and categoryTitle
it currently holds 2 rows of data, the categoryId’s = 1 and 2 and the categoryTitles = News and Blog, in the the userMenuTable I keep a record of what categories that user has selected, the table has 3 columns, menuEntryId, categoryId and cookieId, this table keeps a record of which cookie has which category selected, the ID is to then run these queries,

The first query, gets the users selected categories

function getMenu($cookieId) {
  $this->db->select('*');
  $this->db->from('categoryTable');
  $this->db->join('userMenuTable', 'categoryTable.categoryId = userMenuTable.categoryId', 'left');
  $this->db->where('userMenuTable.cookieId', $cookieId);

  $query = $this->db->get();
  return $query->result_array();

 }

The next query gets all the categories that have no cookieId assigned to them,

function getAllMenus($cookieId) {
$sql ="SELECT categoryTable.categoryTitle, categoryTable.categoryId, userMenuTable.cookieId, userMenuTable.menuEntryId, categoryTable.categoryOnline,
categoryTable.categoryIsSpecial, categoryTable.categoryDateCreated, categoryTable.categorySlug, categoryTable.dashboardUserId, categoryTable.categoryAbstract
FROM categoryTable LEFT JOIN userMenuTable
   ON categoryTable.categoryId = userMenuTable.categoryId
 UNION ALL 
 SELECT categoryTable.categoryTitle, categoryTable.categoryId, userMenuTable.cookieId, userMenuTable.menuEntryId, categoryTable.categoryOnline,
categoryTable.categoryIsSpecial, categoryTable.categoryDateCreated, categoryTable.categorySlug, categoryTable.dashboardUserId, categoryTable.categoryAbstract FROM categoryTable RIGHT JOIN userMenuTable
   ON categoryTable.categoryId = userMenuTable.categoryId
 WHERE userMenuTable.cookieId = NULL";

$query = $this->db->query($sql);
return $query->result_array();
}

however this returns an array that looks like this,

[0] => Array
    (
        [categoryId] => 1
        [categoryTitle] => blog
        [categoryAbstract] => <p>asdsdsadasdsadfdsgdgdsgdsgssssssssssss</p>
        [categorySlug] => blog
        [categoryIsSpecial] => 0
        [categoryOnline] => 1
        [categoryDateCreated] => 1265123745
        [dashboardUserId] => 0
        [menuEntryId] => 5
        [cookieId] => bang4b696152b4869
    )

[1] => Array
    (
        [categoryId] => 8
        [categoryTitle] => News
        [categoryAbstract] => <p>The world at Bang Marketing moves fast, keep up to date w
        [categorySlug] => news
        [categoryIsSpecial] => 0
        [categoryOnline] => 1
        [categoryDateCreated] => 1265283717
        [dashboardUserId] => 0
        [menuEntryId] => 6
        [cookieId] => bang4b696152b4869
    )

[2] => Array
    (
        [categoryTitle] => blog
        [categoryId] => 1
        [cookieId] => bang4b696152b4869
        [menuEntryId] => 5
        [categoryOnline] => 1
        [categoryIsSpecial] => 0
        [categoryDateCreated] => 1265123745
        [categorySlug] => blog
        [dashboardUserId] => 0
        [categoryAbstract] => <p>asdsdsadasdsadfdsgdgdsgdsgssssssssssss</p>
    )

[3] => Array
    (
        [categoryTitle] => News
        [categoryId] => 8
        [cookieId] => bang4b696152b4869
        [menuEntryId] => 6
        [categoryOnline] => 1
        [categoryIsSpecial] => 0
        [categoryDateCreated] => 1265283717
        [categorySlug] => news
        [dashboardUserId] => 0
        [categoryAbstract] => <p>The world at Bang Marketing moves fast, keep up to date w
    )
)

Somehow I need to build a query that returns all the categories that are in the categoryTable and checks that against there it’s Id matches one that is in the userMenuTable where the cookieId matches that of the users, and then return an array so I can loop through it like this,

 if(isset($mainMenu)) {
   //die(print_r($mainMenu));
   foreach ($mainMenu as $k => $v) {
    if($v['menuEntryId'] == '') {
     echo "<li class='menuItem'>
     <a href='".base_url()."welcome/getContent/$v[categoryId]' class='navLink' id='$v[categoryTitle]'>".$v['categoryTitle']."</a>
     </li>";
    } else {
     echo "<li class='menuItem'>
     <a href='".base_url()."welcome/getContent/$v[categoryId]' class='saved navLink' id='$v[categoryTitle]'>".$v['categoryTitle']."</a>
     </li>";
    }
   }
  } else {
   // do something else
   //echo "here";
  }

Answer 1

When you run a left join here you’ll get all your categoryTable items in the left columns and null values in userMenuTable columns. You can use this to your advantage because categories that have not been saved will contain null values for the userMenuTable columns.

SELECT categoryTable.*, userMenuTable.*
FROM categoryTable LEFT JOIN userMenuTable ON categoryTable.categoryID = userMenuTable.categoryID
WHERE userMenuTable.cookieID == '{$cookieID}' OR userMenuTable.cookieID IS NULL;

This might give you a result that looks something like this:

[0] => Array
    (
        [categoryId] => 1
        [categoryTitle] => blog
        [categoryAbstract] => <p>asdsdsadasdsadfdsgdgdsgdsgssssssssssss</p>
        [categorySlug] => blog
        [categoryIsSpecial] => 0
        [categoryOnline] => 1
        [categoryDateCreated] => 1265123745
        [dashboardUserId] => 0
        [menuEntryId] => 5
        [cookieId] => bang4b696152b4869
    )

[1] => Array
    (
        [categoryId] => 8
        [categoryTitle] => News
        [categoryAbstract] => <p>The world at Bang Marketing moves fast, keep up to date w
        [categorySlug] => news
        [categoryIsSpecial] => 0
        [categoryOnline] => 1
        [categoryDateCreated] => 1265283717
        [dashboardUserId] => 0
        [menuEntryId] => 6
        [cookieId] => bang4b696152b4869
    )

[2] => Array
    (
        [categoryId] => 9
        [categoryTitle] => Extra
        [categoryAbstract] => <p>Another category you haven't saved
        [categorySlug] => extra
        [categoryIsSpecial] => 0
        [categoryOnline] => 1
        [categoryDateCreated] => 1265283717
        [dashboardUserId] => 0
        [menuEntryId] => NULL
        [cookieId] => NULL
    )
)