Question

I have table of 5000+ rows and 8+ columns like,

Station Lat Long    Date    Rainfall    Temp    Humidity    Windspeed
Abcd    -   -   09/09/1996  -   -   -   -
Abcd    -   -   10/09/1996  -   -   -   -
Abcd    -   -   11/09/1996  -   -   -   -
Abcd    -   -   12/09/1996  -   -   -   -
Efgh    -   -   09/09/1996  -   -   -   -
Efgh    -   -   10/09/1996  -   -   -   -
Efgh    -   -   11/09/1996  -   -   -   -
Efgh    -   -   12/09/1996  -   -   -   -

I am developing a web application, in that user will select a column like rainfall/temp/humidity and for a particular date.

Can anyone guide me how to query for this in php-postgres. (database:postgres, table:weatherdata, user:user, password:password)

Thanks in advance.

Answer 1

You can use some code like this:

public function getData ($date, $columnsToShow = null) {

  /* You could check the parameters here:
   *   $date is string and not empty
   *    $columnsToShow is an array or null.
   */ 

  if (isset ($columnsToShow))
    $columnsToShow = implode (',', $columnsToShow);
  else  $columnsToShow = "*";

  $query = "select {$columnsToShow}
            from table
            where date = '{$date}'";

  $result = array();
  $conex = pg_connect ("host=yourHost user=yourUser password=yourUser dbname=yourDatabase");
  if (is_resource ($conex)) {
    $rows = pg_query ($conex, $query);

    if ($rows) {
      while ($data = pg_fetch_array ($rows, null, 'PGSQL_ASSOC'))
         $result[] = $data;
    }
  }
  return (empty ($result) ? null : $result);
}

Now you can invoke, for example, like this:

getData ('2012-03-21', array ('Station', 'Rainfall'));

I hope you serve.