Question

Why this query return with error of duplicate id? I’m using php

SELECT DISTINCT * FROM products  as prd
    LEFT OUTER JOIN  (SELECT DISTINCT * FROM product_aliases) AS product_aliases
    ON product_aliases.product_id = prd.id 
    AND product_aliases.alias = '$alias'

    LEFT OUTER JOIN  (SELECT DISTINCT * FROM product_images as prdim
        LEFT OUTER JOIN  product_image_votes as prdimvt 
            ON prdimvt.product_image_id = prdim.id) AS productimages 
    ON productimages.product_id = prd.id 
WHERE prd.id = $id

ERROR:

Database Error Error: SQLSTATE[42S21]: Column already exists: 1060
Duplicate column name ‘id’ SQL Query: SELECT DISTINCT * FROM products
as prd LEFT OUTER JOIN (SELECT DISTINCT * FROM product_aliases) AS
product_aliases ON product_aliases.product_id = prd.id AND
product_aliases.alias = ‘Pringles The Original’ LEFT OUTER JOIN
(SELECT DISTINCT * FROM product_images as prdim LEFT OUTER JOIN
product_image_votes as prdimvt ON prdimvt.product_image_id = prdim.id)
AS productimages ON productimages.product_id = prd.id WHERE prd.id = 1

Answer 1

You have 3 tables in your query and it is possible at least 2 of them have the same column id. Using * in your select would select all columns in these three tables selecting id multiple times

You could solve this by specifying the columns using the alias

SELECT DISTINCT prd.id, prd.Name FROM products  as prd
LEFT OUTER JOIN  (SELECT DISTINCT * FROM product_aliases) AS product_aliases
ON product_aliases.product_id = prd.id 
AND product_aliases.alias = '$alias'
... rest of your query here

You could also do

SELECT DISTINCT prd.* FROM products  as prd

if you don’t want to list them one by one