Question

我有一个名为＆＃39; resources＆＃39;

的表格

Machine     Host        Enabled
mach1       host1       TRUE
mach2       host1       FALSE
mach3       host1       FALSE
mach4       host2       TRUE
mach5       host2       TRUE

我想获取与其关联的所有资源/机器的Enabled为True的主机列表。

我尝试了sql查询 -

select distinct Host from resources where Enabled = TRUE;

但是那个查询让我回到host1和host2作为答案，而我期待答案只是host2。任何人都可以帮我一个可以实现这个的SQL查询吗？

Answer 1

试试这个：

SELECT Host
FROM resources
GROUP BY Host        
HAVING COUNT(*) = COUNT(CASE WHEN Enabled = True THEN 1 END)

或：

SELECT DISTINCT Host 
FROM resources AS r1
WHERE Enabled = TRUE AND 
      NOT EXISTS (SELECT 1 
                  FROM resources AS r2
                  WHERE r1.Host = r2.Host AND r2.enabled = FALSE)

Answer 2

尝试这个并让我知道。

SELECT DISTINCT(Host)
FROM Resources
WHERE Enabled = TRUE AND Host NOT IN (Select Host FROM Resources WHERE Enabled = FALSE)

Answer 3

尝试

select distinct Host from resources res1 where not exist (
   select 1 from resources res2 WHERE res1.host = res2.host AND Enabled = FALSE limit 1
);

Answer 4

这也有效

select host from resources e
having count(e.host)=(select count(enebled) from resources 
                    where enebled='TRUE' and host = e.host)
group by host;

SQL Query获取唯一列表

4 个答案: