sql - 如何从选择子查询中存储多个值

Question

您好我在以下查询中遇到问题：

Update tbl 
set somecol = somecol 
Where Key = (select key  
             from tbl
             group by key 
             having count(*) > 1)  
  and Time = (select max(time) from tbl) 

当只有一个键时，上述查询工作正常。但是，如果有多个键，则此查询不起作用。如何存储来自选择子查询的多个值？时间列也可以是多个。我是 sql 新手。请指导。提前致谢。

Answer 1

使用IN谓词：

Update tbl 
set somecol = somecol 
Where Key in (select key  
             from tbl
             group by key 
             having count(*) > 1)  
  and Time = (select max(time) from tbl)

Answer 2

尝试以下操作：

Update tbl 
set somecol = somecol 
Where Key in (select key  
             from tbl
             group by key 
             having count(*) > 1)  
  and Time in (select max(time) from tbl) 

根据要求，您还可以使用派生表。