Question

为什么此查询返回错误的重复ID？我正在使用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：

数据库错误错误：SQLSTATE [42S21]：列已存在：1060 重复的列名'id'SQL查询：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 （选择DISTINCT * FROM product_images作为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

您的查询中有3个表，其中至少有2个表具有相同的列id。在您的选择中使用*会选择这三个表中的所有列，多次选择id

您可以通过使用别名

指定列来解决此问题

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

您也可以

SELECT DISTINCT prd.* FROM products  as prd

如果您不想逐一列出

查询错误重复列id sql

1 个答案: