Question

查询

select brand
from products
where status = false
and brand not in (
  select brand
  from products
  where status = true
  group by brand
)
group by brand;

基本上，我想只选择那些在任何产品中都没有status = true的品牌。

我想优化上述查询

Answer 1

使用布尔聚合函数bool_or()：

select brand
from products
group by brand
having not bool_or(status);

Answer 2

您可以使用CASE语句将布尔值转换为位，然后使用MAX：

SELECT brand
FROM products
GROUP BY brand
HAVING MAX(CASE WHEN status = TRUE THEN 1 ELSE 0 END) = 1

如何选择那些在任何产品中都没有status = true的品牌

2 个答案: