Fetching rows or columns from result sets in PHP (PDO)

After executing a statement that returns one or more result sets, use one of the methods available in the PDO API to iterate through the returned rows. The PDO API also provides methods to fetch a single column from one or more rows in the result set.

To fetch data from a result set:

1. Fetch data from a result set by calling one of the fetch methods:
   • To return a single row from a result set as an array or object, call the PDOStatement::fetch method.
   • To return all of the rows from the result set as an array of arrays or objects, call the PDOStatement::fetchAll method.
   By default, PDO returns each row as an array indexed by the column name and 0-indexed column position in the row. To request a different return style, specify one of the PDO::FETCH_* constants as the first parameter when you call the PDOStatement::fetch method:

   PDO::FETCH_ASSOC

   Returns an array indexed by column name as returned in your result set.

   PDO::FETCH_BOTH (default)

   Returns an array indexed by both column name and 0-indexed column number as returned in your result set

   PDO::FETCH_BOUND

   Returns TRUE and assigns the values of the columns in your result set to the PHP variables to which they were bound with the PDOStatement::bindParam method.

   PDO::FETCH_CLASS

   Returns a new instance of the requested class, mapping the columns of the result set to named properties in the class.

   PDO::FETCH_INTO

   Updates an existing instance of the requested class, mapping the columns of the result set to named properties in the class.

   PDO::FETCH_LAZY

   Combines PDO::FETCH_BOTH and PDO::FETCH_OBJ, creating the object variable names as they are accessed.

   PDO::FETCH_NUM

   Returns an array indexed by column number as returned in your result set, starting at column 0.

   PDO::FETCH_OBJ

   Returns an anonymous object with property names that correspond to the column names returned in your result set.

   If you requested a scrollable cursor when you called the PDO::query or PDOStatement::execute method, you can pass the listed optional parameters that control which rows are returned to the caller:

   • One of the PDO::FETCH_ORI_* constants that represents the fetch orientation of the fetch request:

     PDO::FETCH_ORI_NEXT (default)

     Fetches the next row in the result set.

     PDO::FETCH_ORI_PRIOR

     Fetches the previous row in the result set.

     PDO::FETCH_ORI_FIRST

     Fetches the first row in the result set.

     PDO::FETCH_ORI_LAST

     Fetches the last row in the result set.

     PDO::FETCH_ORI_ABS

     Fetches the absolute row in the result set. Requires a positive integer as the third argument to the PDOStatement::fetch method.

     PDO::FETCH_ORI_REL

     Fetches the relative row in the result set. Requires a positive or negative integer as the third argument to the PDOStatement::fetch method.

   • An integer requesting the absolute or relative row in the result set, corresponding to the fetch orientation requested in the second argument to the PDOStatement::fetch method.
2. Optional: Fetch a single column from one or more rows in a result set by calling one of the listed methods:
   • To return a single column from a single row in the result set:

     Call the PDOStatement::fetchColumn method, specifying the column you want to retrieve as the first argument of the method. Column numbers start at 0. If you do not specify a column, the PDOStatement::fetchColumn returns the first column in the row.

   • To return an array that contains a single column from all of the remaining rows in the result set:

     Call the PDOStatement::fetchAll method, passing the PDO::FETCH_COLUMN constant as the first argument, and the column you want to retrieve as the second argument. Column numbers start at 0. If you do not specify a column, calling PDOStatement::fetchAll(PDO::FETCH_COLUMN) returns the first column in the row.

   For more information about the PDO API, see http://php.net/manual/en/book.pdo.php.

$stmt = $conn->query("SELECT firstnme, lastname FROM employee");
while ($row = $stmt->fetch(PDO::FETCH_NUM)) {
  print "Name: <p>{$row[0] $row[1]}</p>";
}