Question

example:

$query = $mydb->query('PRAGMA table_info("mytable")');
//variable query has now type of PDOStatement Object
print_r($query->fetchAll(PDO::FETCH_COLUMN,1)); // this result is ok
print_r($query->fetchAll(PDO::FETCH_COLUMN,2)); // but this result gives empty array

so is there any way to reuse statement object ?

Answer 1

A PDOStatement Object returns false when there are no more rows available. The call to fetchAll covers all rows which would then always return false on any following attempt to fetch. This limits the reuse of the statement object. You can use the PDOStatement::bindColumn to achieve what it looks as if you are attempting in your example.

$query = $mydb->query('PRAGMA table_info("mytable")');
// Variables passed to be bound are passed by reference.
// Columns are based on a *1* index or can be referenced by name.
$query->bindColumn(1, $bound_column1);
$query->bindColumn(2, $bound_column2);

$query->fetchAll();
print_r($bound_column1);
print_r($bound_column2);