Question

Possible Duplicate:
Split string in SQL
Searching a column with comma seperated values

In my PHP project I’m facing a problem to write a SQL:

I have a table “consultants” with fields categories which has values like:

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+ id |  consultant_name  | categories                           +
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+  1 |  AOAOAO           | health,insurance,programming,        +
+  2 |  BOBOBO           | health,gaming,windows,mobile,        +
+  3 |  CCCCCC           | insurance,windows,                   + 
+  4 |  DDDDDD           | mobile,                              +
+  . |  ......           | ............                         +
+  . |  ......           | ............                         +
+  . |  ......           | ............                         +
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

And I have an array which contains all the categories that a consultant can register with.

$arrayOfCategories =  $array("health","insurance","programming",
                             "sports","gaming","windows","apple",
                             "mobile","astrology");

What I want is a SQL Query that should give me an output like:

+++++++++++++++++++++++++++++++
+ category      | occurrence  +    
+++++++++++++++++++++++++++++++
+ health        | 2           +
+ insurance     | 2           +
+ programming   | 1           +
+ sports        | 0           +
+ gaming        | 1           +
+ windows       | 2           +
+ apple         | 0           +
+ mobile        | 2           +
+ astrology     | 0           +
+++++++++++++++++++++++++++++++

Any kind of help will be appreciated…

Thanks In Advance…

Answer 1

Bad database design but interesting question, here it is my way to do (php code):

$arrayOfCategories =  $array("health","insurance","programming",
                             "sports","gaming","windows","apple",
                             "mobile","astrology");

 $count = count($arrayOfCategories);
 $query = "";
 for($i = 0; $i < $count; $i++)
 {
   $value = $arrayOfCategories[$i];
   $query += "SELECT '$value' AS category,
                 COUNT(*) AS occurrence
                 FROM consultants
                 WHERE FIND_IN_SET('$value', categories)";
    if($i < $count -1) {
    $query += " UNION "
    }


 }

The result of the generated query should give you exactly what you want . Often from a bad design comes interesting questions … 🙂