为什么distinct在这里不起作用 [英] Why distinct is not working here

问题描述

SELECT prl.description ,
               DISTINCT
convert(varchar,prl.effective_date,103) effective_date,
    b.description brand  ,
     pc.description cat 
     FROM ProductRateList prl,Products pro,ProductCatg pc, Brands b  
     WHERE pro.Id = prl.Product_Id AND pc.Id = pro.ProdCatg_Id  AND B.Id = pro.Brand_id  AND pro.Active = 'Y' 
     order by prl.effective_date desc, 
     PRl.description ASC 
     group by convert(varchar,prl.effective_date,103),prl.description

推荐答案

这可以用作精确的解决方案，该解决方案也将具有按函数顺序和按函数分组的顺序

And this could be used as exact solution which will have the order by and as well as the group by function too

SELECT DISTINCT  prl.description ,
   convert(varchar,prl.effective_date,103) effective_date,
  b.description brand  ,
   pc.description cat
   FROM ProductRateList prl,Products pro,ProductCatg pc, Brands b
   WHERE pro.Id = prl.Product_Id AND pc.Id = pro.ProdCatg_Id  AND B.Id = pro.Brand_id  AND pro.Active = 'Y'
    group by convert(varchar,prl.effective_date,103),prl.description , b.description   ,
   pc.description
   ORDER BY prl.Description

order by只能包含具有汇总功能或具有不同功能的列

order by can contain only those column who either have aggregate function or have distinct

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