How to get last run query in CakePHP 3.2?

In plain English: All you need to do is modify config/app.php

Find the Datasources configuration and set 'log' => true

'Datasources' => [
    'default' => [
        'className' => 'Cake\Database\Connection',
        'driver' => 'Cake\Database\Driver\Mysql',
        'persistent' => false,
        'host' => 'localhost',

        ...

        'log' => true,  // Set this
    ]
]

If your app is in debug mode, you will now see the SQL query when your page displays a SQL error. If you do not have debug mode on, you can log the SQL queries to a file by also adding the following:

config/app.php

Find the Log configuration and add a new log type:

'Log' => [
    'debug' => [
        'className' => 'Cake\Log\Engine\FileLog',
        'path' => LOGS,
        'file' => 'debug',
        'levels' => ['notice', 'info', 'debug'],
        'url' => env('LOG_DEBUG_URL', null),
    ],
    'error' => [
        'className' => 'Cake\Log\Engine\FileLog',
        'path' => LOGS,
        'file' => 'error',
        'levels' => ['warning', 'error', 'critical', 'alert', 'emergency'],
        'url' => env('LOG_ERROR_URL', null),
    ],

    // Add the following...

    'queries' => [
        'className' => 'File',
        'path' => LOGS,
        'file' => 'queries.log',
        'scopes' => ['queriesLog']
    ]
],

Your SQL queries will now be written to a log file which you can find in /logs/queries.log