Examples

Joins

Description

join() matches rows of two frames on column values, as SQL does: Join::inner, left, right or left_anti. join_prefix renames the right side's columns, so names never collide. The right frame is read whole (held in memory, spilled past the memory limit); to look up only what each batch needs, use joinEach().

Documentation

A join matches rows from two frames on a condition.

Join

Code

<?php

declare(strict_types=1);

use function Flow\ETL\DSL\{data_frame, from_array, join_on, to_output};
use Flow\ETL\Join\Join;

require __DIR__ . '/vendor/autoload.php';

$users = [
    ['id' => 1, 'name' => 'John'],
    ['id' => 2, 'name' => 'Jane'],
    ['id' => 3, 'name' => 'Doe'],
    ['id' => 4, 'name' => 'Bruno'],
];

$emails = [
    ['id' => 2, 'email' => 'john@email.com'],
    ['id' => 3, 'email' => 'jane@emial.com'],
    ['id' => 4, 'email' => 'bruno@email.com'],
];

data_frame()
    ->read(from_array($users))
    ->join(
        data_frame()->read(from_array($emails)),
        join_on(['id' => 'id'], join_prefix: 'joined_'),
        Join::left
    )
    ->collect()
    ->write(to_output(truncate: false))
    ->run();

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