我有一张包含这样记录的表
*************************** 1. row *************************
did: 98
brand_name: Aarther P (100+500)
generic: Paracetamol, Aceclofenac
tradename: Aarther P (100+500)
manfactured: Rekvina Pharmaceuticals
unit: 500mg/100mg
type: Tablet
quantity: 10Tablet
price: 27.9
*************************** 2. row *************************
did: 99
brand_name: Aarther-P
generic: Aceclofenac, Paracetamol
tradename: Aarther-P
manfactured: Rekvina Pharmaceuticals
unit: 100mg/500mg
type: Tablet
quantity: 10Tablet
price: 27.9
*************************** 3. row ************************
did: 100
brand_name: Aarticef (1000mg)
generic: NULL
tradename: Aarticef (1000mg)
manfactured: Alpic Remedies Ltd
unit: 1000mg/vial
type: Injection
quantity: 1Vial
price: 96
我想消除重复的制造名称，因为我已经执行了以下查询
select brand_name,generic,manfactured from drugs_info group by
manfactured;
但它只显示第1和第3条记录，但我想要第2条记录
*************************** 1. row *************************
did: 98
brand_name: Aarther P (100+500)
generic: Paracetamol, Aceclofenac
tradename: Aarther P (100+500)
manfactured: Rekvina Pharmaceuticals
unit: 500mg/100mg
type: Tablet
quantity: 10Tablet
price: 27.9
*************************** 3. row ************************
did: 100
brand_name: Aarticef (1000mg)
generic: NULL
tradename: Aarticef (1000mg)
manfactured: Alpic Remedies Ltd
unit: 1000mg/vial
type: Injection
quantity: 1Vial
price: 96
如何根据我的要求编写选择查询。
答案 0 :(得分：0)
SELECT * FROM
(select brand_name,generic,manfactured from drugs_info ORDER BY did DESC) abc
group by manfactured;
答案 1 :(得分：0)
要删除mysql中的重复项，请使用mysql的多表删除语法：
delete d2
from mytable d1
join mytable d2 on d2.manfactured = d1.manfactured
and d2.did > d1.did
d2.did > d1.did的额外连接条件确保两个行都不会连接到自身，并且每个副本只有一半被删除，而且还保留了最低的id行。