Question

MySQL初学者在这里。我有两个表（如下所示），其中一个（freqs）我想根据数据在参考列（下面的type_freq）上匹配的列插入值。例如，'rs9'（来自freqs）的类型为'GG'，这个'GG'值与type_freq表中的'type2'匹配，我想插入相应的频率（在这种情况下为'。'）到'rs9'的频率值。

我尝试使用案例陈述无济于事。我是否正确地认为这最好用几个案例陈述来解决？还有更好的方法吗？我非常感谢任何反馈。谢谢！

表：

TABLE freqs

rsid       type      freq
rs9         GG
rs8         CC
rs1         CC

TABLE type_freq

 rid       type1    type1_frequency    type2   type2_frequency   type3     type3_frequency
 rs9       AA        .7                GG        .2             GC         .1
 rs8       CC        .5                TT        .3             AT         .2
 rs1       AA        .9                CC        .1             .          .

我的代码：

 UPDATE freqs SET req = 
     (
(SELECT type1_Frequency CASE 
    WHEN type.freqs = type1.type_frequencies
            FROM type_frequencies
    END CASE)
(SELECT type2_Frequency CASE
    WHEN type.freqs = type2.type_frequncies
            FROM type_frequencies
    END CASE)
(SELECT type3_Frequency CASE
    WHEN type.freqs = type3.type_frequencies
            FROM type_frequencies
    END CASE)
    )

Answer 1

首先，让我们设计一个查询，创建type_freq表的规范化版本：

SELECT rid, type1 AS type, type1_frequency AS frequency
FROM type_freq
UNION ALL
SELECT rid, type2 AS type, type2_frequency AS frequency
FROM type_freq
UNION ALL
SELECT rid, type3 AS type, type3_frequency AS frequency
FROM type_freq

现在让我们用这个来更新你的表：

UPDATE freqs
SET freq =
(
    SELECT frequency
    FROM
    (
        SELECT rid, type1 AS type, type1_frequency AS frequency
        FROM type_freq
        UNION ALL
        SELECT rid, type2 AS type, type2_frequency AS frequency
        FROM type_freq
        UNION ALL
        SELECT rid, type3 AS type, type3_frequency AS frequency
        FROM type_freq
    ) x
    WHERE x.type = freqs.type AND x.rid = freqs.rsid
)

请注意，如果您可以控制数据库架构，我建议您永久规范化type_freq表。

根据列值匹配来插入值

1 个答案: