array &getCol
     ( 
    
      string $query
    
     , 
      string $type
       = null
    
     , 
      array 
      $params = array()
     
    
     , 
      array $param_types
       = null
    
     , 
      mixed 
      $colnum = 0
     
    
   )
Fetch a single column from a result set of a query. The function takes care of doing the query and freeing the results when finished.
$query
     the SQL query
$type
     if supplied, the type of the column in the result set will be set for fetching
$params
     if supplied, prepareQuery()/ executeQuery() will be used with this array as execute parameters
$param_types
     if supplied, the values in $param will automatically set to the passed datatypes
$colnum
     which column to return (integer [column number, starting at 0] or string [column name])
   array - the first row of results as an array
     indexed from 0 or a MDB_Error, if fail
    
| Error code | Error message | Reason | Solution | 
|---|---|---|---|
| MDB_ERROR_INVALID | NULL | SQL statement for preparing is not valid. | See the prepareQuery() documentation, if you want to use a SQL statemt using wildcards. | 
| MDB_ERROR_NEED_MORE_DATA | NULL | To less data for filling the prepared SQL statement. | Check the number of wild cards given in the SQL statement
          
         prepareQuery()
        . Check the count of
          entries in the array for $params. The count
          of entries have to be equal to the number of wild cards. | 
| MDB_ERROR_NO_DB_SELECTED | NULL | No database was chosen. | Check the DSN in connect() . | 
| MDB_ERROR_TRUNCATED | NULL | The result set contains fewer then two columns | Check the SQL query or choose another get*() function | 
| every other error code | Database specific error | Check the database related section of PHP-Manual to detect the reason for this error. In the most cases a misformed SQL statement. Ie. using LIMIT in a SQL-Statement for an Oracle database. | 
This function can not be called statically.
query() , limitQuery() , prepareQuery() , executeQuery() , getRow() , getOne() , getAssoc()