Question

我有点头疼试图弄清楚如何创建一个合适的MySQL查询来检索我需要的信息。以下是我的TABLE PARAM中的示例行：

Serial | Repeater1 | Repeater2 | Repeater3

我想检索不在Serial字段中的所有Repeater1，Repeater2或Repeater3。所有这些字段都在同一个表中。

例如：

Serial | Repeater1 | Repeater2 | Repeater3

1234   | 1111      | 2222      | null

1235   | 1111      | null      | null

1236   | 1234      | 1111      | 2222

我的SELECT查询应仅返回：

1111

2222

由于Repeater1中使用的1234存在于Serial（因此需要避免），即使1111或2222存在于不同列（本例中为Repeater2和Repeater3）下，我只想列出DISTINCT Repeater1，Repeater2或Repeater3不是串行。

您有任何想法要完成此请求吗？

许多人提前帮忙！

Answer 1

select * from ( 
    select distinct Repeater1 as repeater from table1 where Repeater1 is not null 
    UNION 
    select distinct Repeater2 as repeater from table1 where Repeater2 is not null 
    UNION 
    select distinct Repeater3 as repeater from table1 where Repeater3 is not null 
) as datarepeater 
where datarepeater.repeater not in (select serial from table1) and datarepeater.repeater!=0

Answer 2

select r from (
    select Repeater1 as r from t WHERE Repeater1 IS NOT NULL
    union 
    select Repeater2 as r from t  WHERE Repeater2 IS NOT NULL
    union 
    select Repeater3 as r from t  WHERE Repeater3 IS NOT NULL
) reps
left join t
on reps.r = t.Serial 
WHERE t.Serial IS NULL

MySQL组合/ Concat /多选查询

2 个答案: