On the problem of multi-table join query to eliminate duplicate rows

wshch0725

I have 3 tables, a product table, and 2 different types of classification tables. One is necessary for classification and the other is not necessary. My SQL statement is as follows:

select distinct(int_product_id),str_productCatalog_title,
str_product_name,str_brandcatalog_title,str_Product_ProduceArea,
str_Product_Standard,dat_Product_CreateTime,int_Product_IsFocus,
int_Product_IsHot,int_Product_SortID
FROM Sunyes_Product inner join Sunyes_ProductCatalog on
str_Product_CatalogCode = str_ProductCatalog_SelfCode left JOIN
Sunyes_ProductBrandCatalog ON str_Product_BrandCode=str_BrandCatalog_SelfCode

But there are many duplicate rows in the queried data. Why?
How to modify it?

mydriver

The most likely reason is that str_Product_CatalogCode in Sunyes_ProductCatalog cannot uniquely identify a record and is duplicated; or str_Product_BrandCode in Sunyes_ProductBrandCatalog is duplicated.
How to fix this problem depends on which of the three tables all the fields in your SELECT are taken from.