sql - 在子集中具有特定值的父的 SQL 查询

Question

我试图只返回一组子项包含多个特定记录的父项。鉴于此表：

Product   State
-------   -----
111       AZ
111       CA
111       UT
222       AZ
222       WA
333       CA

我想找到Product既有AZ子记录又有CA子记录的列表，即使它还有其他记录。哪个会返回...

Product
-------
111

Answer 1

select product  
  from table 
 where state in ('az','ca')  
 group by product 
having count(distinct(state)) = 2


select distinct product  
  from table 
 where state = 'az'
INTERSECT 
select distinct product  
  from table 
 where state = 'ca'  


select distinct t1.product  
  from table t1 
  join table t2 
    on t1.product = t2.product 
   and t1.state = 'az'
   and t2.state = 'ca'

最后一个可能是最有效的。

Answer 2

SELECT product 
FROM table 
GROUP BY product 
HAVING SUM(CASE WHEN State 'AZ' THEN 1 ELSE 0 END) > 1
   AND SUM(CASE WHEN State 'CA' THEN 1 ELSE 0 END) > 1