SQLite3::query

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

SQLite3::query — Executes an SQL query

说明

public SQLite3::query ( string $query ) : SQLite3Result|false

Executes an SQL query, returning an SQLite3Result object. If the query does not yield a result (such as DML statements) the returned SQLite3Result object is not really usable. Use SQLite3::exec() for such queries instead.

参数

query: The SQL query to execute.

返回值

Returns an SQLite3Result object, 或者在失败时返回 false.

范例

Example #1 SQLite3::query() example


<?php
$db = new SQLite3('mysqlitedb.db');

$results = $db->query('SELECT bar FROM foo');
while ($row = $results->fetchArray()) {
    var_dump($row);
}
?>

User Contributed Notes

paule-panke at example dot com 12-Feb-2017 01:55


Check with SQLite3Result::numColumns() for an empty result before calling SQLite3Result::fetchArray().



In contrast to the documentation SQLite3::query() always returns a SQLite3Result instance, not only for queries returning rows (SELECT, EXPLAIN). Each time SQLite3Result::fetchArray() is called on a result from a result-less query internally the query is executed again, which will most probably break your application.

For a framwork or API it's not possible to know in before whether or not a query will return rows (SQLite3 supports multi-statement queries). Therefore the argument "Don't execute query('CREATE ...')" is not valid.

bohwaz 13-Mar-2013 11:47


The recommended way to do a SQLite3 query is to use a statement. For a table creation, a query might be fine (and easier) but for an insert, update or select, you should really use a statement, it's really easier and safer as SQLite will escape your parameters according to their type. SQLite will also use less memory than if you created the whole query by yourself. Example:



<?php



$db = new SQLite3;

$statement = $db->prepare('SELECT * FROM table WHERE id = :id;');

$statement->bindValue(':id', $id);



$result = $statement->execute();



?>



You can also re-use a statement and change its parameters, just do $statement->reset(). Finally don't forget to close a statement when you don't need it anymore as it will free some memory.