去除重复数据,该怎么处理

去除重复数据
create table tbqc
(
id int,
name varchar(30),
sex varchar(30),
age int 
)
insert tbqc
select 1,'a','nv',20 union all
select 1,'a','nv',20 union all
select 2,'b','nan',20 union all
select 2,'b','nan',20 union all
select 3,'c','nan',20 union all
select 4,'d','nv',20 union

[解决办法]

SQL code

create table tbqc(id int,name varchar(30),sex varchar(30),age int )insert tbqcselect 1,'a','nv',20 union allselect 1,'a','nv',20 union allselect 2,'b','nan',20 union allselect 2,'b','nan',20 union allselect 3,'c','nan',20 union allselect 4,'d','nv',20select distinct * from tbqc/*id          name                           sex                            age----------- ------------------------------ ------------------------------ -----------1           a                              nv                             202           b                              nan                            203           c                              nan                            204           d                              nv                             20*/
[解决办法]
SQL code
select distinct * from tbqc/*id          name                           sex                            age----------- ------------------------------ ------------------------------ -----------1           a                              nv                             202           b                              nan                            203           c                              nan                            204           d                              nv                             20(4 行受影响)*/
[解决办法]
数据表设计的时候是应该有主键的，有主键的情况下是不可能出现完全相同的数据的。
[解决办法]
[select distinct * from tbqc=SQL][/code]
[解决办法]
对于表中两行记录完全一样的情况，可以用下面语句获取到去掉重复数据后的记录：
 select distinct * from 表名