[英]SQL check id value from multiple rows
我想根据特定条件计算ID的数量。
我有一个包含3列的表:id(不是唯一的),foo(整数)和bar(字符串)。
id| foo | bar
1| 0 | yes
1| 1 | no
1| 1 | no
2| 0 | no
2| 1 | no
3| 0 | yes
3| 1 | no
3| 2 | yes
4| 0 | yes
我希望查询给我一个ID列表。 条件:
a. id should have more than 1 entry.
b. id needs to have foo = 0 AND bar = yes.
c. if (b) is satisfied, it also needs to have all the rest of foo to have bar = no. (the number of foo for each id is unknown)
在上面的示例中,查询应返回id =1。(Id = 2无效,因为当foo = 0时bar =否,Id = 3无效,因为当foo = 2时bar = yes。)
你可以得到的名单id
使用S group by
和having
。 您的条件的确切翻译是:
select id
from t
group by id
having count(*) > 1 and
sum( foo = 0 and bar = 'yes' ) = 1 and
sum( bar = 'no' ) = count(*) - 1;
如果需要计数而不是列表,则可以使用子查询。
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