sql server 统计数据库中某个字段的值，剔除重复数据和查找重复
1.有的时候，在数据库中存在一些重复的数据，但是我们又想统计某个字段的，重复的要剔除掉，如图所示： 在上面的图我们可以看到，id=2,3 id=4,5的4条数据都重复了，我们统计amount只要其中的一条。sql语句如下： select sum(b.money) as '金额' from (select
1.有的时候，在数据库中存在一些重复的数据，但是我们又想统计某个字段的值，重复的要剔除掉，如图所示：
在上面的图我们可以看到，id=2,3 id=4,5的4条数据都重复了，我们统计amount只要其中的一条。sql语句如下：
select sum(b.money) as '金额' from (select MAX(amount) as money from test group by name) b
2.查找重复的数据
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