Product list query order by references same column more then once.

[dverkade]

Preconditions

1. Magento 2.2.4
2. PHP 7.1

Steps to reproduce

1. Have a category with several products
2. Print the query for retrieving category products.
3. Use the following code in the Magento_Catalog/templates/product.list.phtml to display the query used:

<?php
$_productCollection = $block->getLoadedProductCollection();
print $_productCollection->getSelect();

Expected result

1. ORDER BY should reference the same column only once. In this example it should reference:

ORDER BY 
`cat_index`.`position` asc, 
`e`.`entity_id` asc

Actual result

Query for retrieving products in a category is the following:

SELECT 1 AS `status`, `e`.`entity_id`,`cat_index`.`position` AS `cat_index_position`, `e`.`attribute_set_id`, `e`.`type_id`, `e`.`created_at`, `e`.`updated_at`, `e`.`sku`, `stock_status_index`.`stock_status` AS `is_salable`, `e`.`name`, `e`.`price`, `e`.`image`, `e`.`small_image`, `e`.`tax_class_id`, `e`.`url_key`, `e`.`thumbnail`, `e`.`short_description`, `e`.`special_price`, `e`.`special_from_date`, `e`.`special_to_date`, `e`.`news_from_date`, `e`.`news_to_date`, `e`.`required_options`, `e`.`price_type`, `e`.`weight_type`, `e`.`price_view`, `e`.`image_label`, `e`.`small_image_label`, `e`.`thumbnail_label`, `e`.`links_purchased_separately`, `e`.`msrp_display_actual_price_type`, `e`.`msrp`, `e`.`links_exist`, `e`.`on_home`, `e`.`old_brand`, `e`.`old_brand_value`, `e`.`brand`, `e`.`brand_value`, `e`.`productstatus`, `e`.`productstatus_value`, `e`.`motief`, `e`.`orderable`, `e`.`bss_weight`, `e`.`gift_type`, `e`.`gift_type_value`, `e`.`gift_value`, `e`.`gift_to`, `e`.`gift_from`, `e`.`gift_price_type`, `e`.`gift_price_type_value`, `e`.`gift_template_ids`, `e`.`gift_dropdown`, `e`.`gift_price`, `e`.`stijl_mode`, `e`.`mouwlengte`, `e`.`mouwlengte_value`, `e`.`halslijn`, `e`.`halslijn_value`, `e`.`kledingkleur_specifiek`, `e`.`swatch_image`, `e`.`sale`, `e`.`tt_product_id`, `e`.`new_arrival`, `price_index`.`price`, `price_index`.`tax_class_id`, `price_index`.`final_price`, IF(price_index.tier_price IS NOT NULL, LEAST(price_index.min_price, price_index.tier_price), price_index.min_price) AS `minimal_price`, `price_index`.`min_price`, `price_index`.`max_price`, `price_index`.`tier_price` 
FROM `catalog_product_flat_3` AS `e` 
INNER JOIN `catalog_category_product_index` AS `cat_index` ON cat_index.product_id=e.entity_id AND cat_index.store_id=3 AND cat_index.visibility IN(2, 4) AND cat_index.category_id='1689' 
INNER JOIN `cataloginventory_stock_status` AS `stock_status_index` ON e.entity_id = stock_status_index.product_id AND stock_status_index.website_id = 0 AND stock_status_index.stock_id = 1 
INNER JOIN `catalog_product_index_price` AS `price_index` ON price_index.entity_id = e.entity_id AND price_index.website_id = '1' AND price_index.customer_group_id = 0 
WHERE (stock_status_index.stock_status = 1) 
ORDER BY 
`cat_index_position` asc, 
`cat_index`.`position` asc, 
`e`.`entity_id` asc, 
`e`.`entity_id` DESC, 
`cat_index_position` asc, 
`cat_index`.`position` asc, 
`e`.`entity_id` asc

1. e.entity_id is 3 times present in the query.
2. Reference to column cat_index_position and cat_index.position are the same (in the from part cat_index_position is defined as cat_index.position)

[engcom-backlog-nickolas]

Hello @dverkade, thank you for your report and pull requests. I'm closing this issue as pull requests already have been merged to mainline.