Question

我正在使用sql查询中的一个问题这是我的问题： -

$query = 'SELECT 
          products.id, products.ProductName, products.smallimage as proSmallImage  
          FROM 
          products 
          LEFT JOIN 
          productscolors 
          ON 
          productscolors.proid =products.id  
          WHERE 
          products.id!="'.$productId.'" 
          AND
          products.Enable="YES" 
          AND 
          products.undercatid in("22","16") 
          GROUP BY 
          productscolors.proid 
          ORDER BY 
          rand() limit 0,6';

这个查询对我来说很好，但我面临的一个问题是

您在查询中看到了这一点

products.undercatid in("22","16") group by productscolors.proid order by rand() limit 0,6

这将返回22和16中undercatid的随机数据但我想要来自22个id的3个记录和来自16个id的3个记录我当前的查询提供来自两个查询的随机数据，即（有时它从22个undercatid中获得5个，从16个undercatid中获得1个等）任何人都可以帮我解决这个问题。我想要来自undercatid

的3-3条记录

Answer 1

你可以使用单一选择的联合

select * from ( 
  SELECT  products.id, products.ProductName, products.smallimage as 
  proSmallImage  FROM products  LEFT JOIN productscolors ON 
  productscolors.proid =products.id  where products.id!="'.$productId.'" and 
  products.Enable="YES" and products.undercatid = "22"
  group by productscolors.proid order by rand() 
  limit 0,3
 ) t1 
union all
select * from (
  SELECT  products.id, products.ProductName, products.smallimage as 
  proSmallImage  FROM products  LEFT JOIN productscolors ON 
  productscolors.proid =products.id  where products.id!="'.$productId.'" and 
  products.Enable="YES" and products.undercatid = "16"
  group by productscolors.proid order by rand() 
  limit 0,3 
) t2

Answer 2

    SELECT  products.id, products.ProductName, products.smallimage as proSmallImage  FROM products  where products.undercatid in("22") limit 0,3 
    UNION ALL 
    SELECT  products.id, products.ProductName, products.smallimage as proSmallImage  FROM products where products.undercatid in("16")  limit 0,3 
    LEFT JOIN productscolors ON productscolors.proid =products.id  
    where products.id!="'.$productId.'" and products.Enable="YES" 
    group by productscolors.proid 
    order by rand()

如何以rand的顺序获得相等的记录，限制为6？

2 个答案: