MySQL-on-SQLite does not translate DATE arithmetic with INTERVAL HOUR

Bug

The current MySQL-on-SQLite driver leaves MySQL date arithmetic unchanged, causing SQLite syntax errors for queries such as:

SELECT DATE(start_datetime - INTERVAL 5 HOUR) FROM wp_event_dates;

The executed SQLite query still contains INTERVAL 5 HOUR and fails with:

SQLSTATE[HY000]: General error: 1 near \"5\": syntax error

Runtime

• WordPress Playground / WP Codebox
• WordPress 7.0.2
• PHP 8.3.31
• SQLite integration path: wp-includes/database/sqlite/class-wp-pdo-mysql-on-sqlite.php

Expected

Translate MySQL INTERVAL ... HOUR date arithmetic to an equivalent SQLite datetime modifier so valid WordPress plugin queries can execute under the compatibility layer.

Impact

This blocks focused WordPress PHPUnit coverage for timezone-aware calendar boundaries in Extra-Chill/data-machine-events#489 after its custom test table is successfully created.

Start in wp-includes/database/sqlite/class-wp-pdo-mysql-on-sqlite.php and trace how MySQL date arithmetic is translated before the SQLite query executes. Reproduce the SELECT using INTERVAL 5 HOUR, then verify that the generated SQLite datetime expression runs without a syntax error and supports the stated WordPress plugin query.