根据另一列中的不同值设置列值 [英] set column value based on distinct values in another column

问题描述

我正在尝试做与此问题非常相似的事情: mysql-更新基于其他行的行

I am trying to do something very similar to this question: mysql - UPDATEing row based on other rows

我有一个名为modset的表，其格式如下:

I have a table, called modset, of the following form:

member    year    y1    y2    y3    y1y2    y2y3    y1y3    y1y2y3 
a         1       0     0     0     0       0       0       0
a         2       0     0     0     0       0       0       0
a         3       0     0     0     0       0       0       0
b         1       0     0     0     0       0       0       0
b         2       0     0     0     0       0       0       0
c         1       0     0     0     0       0       0       0
c         3       0     0     0     0       0       0       0
d         2       0     0     0     0       0       0       0

第3列，第9列是二进制标志，用于指示该成员具有记录的年份组合.因此，我希望SQL更新的结果如下所示:

Columns 3:9 are binary flags to indicate which combination of years the member has records in. So I wish the result of an SQL update to look as follows:

member    year    y1    y2    y3    y1y2    y2y3    y1y3    y1y2y3 
a         1       0     0     0     0       0       0       1
a         2       0     0     0     0       0       0       1
a         3       0     0     0     0       0       0       1
b         1       0     0     0     1       0       0       0
b         2       0     0     0     1       0       0       0
c         1       0     0     0     0       0       1       0
c         3       0     0     0     0       0       1       0
d         2       0     1     0     0       0       0       0

上面链接的问题中的代码执行的操作非常接近，但仅当它是成员拥有记录的不同年份的计数时.我需要根据成员拥有记录的年份的特定值来建立列.

The code in the question linked above does something very close but only when it is a count of the distinct years in which the member has records. I need to base the columns on the specific values of the years in which the member has records.

提前谢谢！

解决方案

SELECT member,
    case when min(distinct(year)) = 1 and max(distinct(year)) = 1 then 1 else 0 end y1,
    case when min(distinct(year)) = 1 and max(distinct(year)) = 2 then 1 else 0 end y1y2,
    case when min(distinct(year)) = 1 and max(distinct(year)) = 3 and count(distinct(year)) = 2 then 1 else 0 end y1y3,
    case when min(distinct(year)) = 1 and max(distinct(year)) = 3 and count(distinct(year)) = 3 then 1 else 0 end y1y2y3,
    case when min(distinct(year)) = 2 and max(distinct(year)) = 2 then 1 else 0 end y2,
    case when min(distinct(year)) = 2 and max(distinct(year)) = 3 then 1 else 0 end y2y3,
    case when min(distinct(year)) = 3 then 1 else 0 end y3
INTO temp5
FROM modset
GROUP BY member;

UPDATE modset M
SET y1 = T.y1, y2 = T.y1, y3 = T.y3, y1y2 = T.y1y2, y1y3 = T.y1y3, y2y3 = T.y2y3, y1y2y3 = T.y1y2y3
FROM temp5 T
WHERE T.member = M.member;

推荐答案

您要使用什么查询来返回成员拥有记录的年份的指标?

What is the query you are using to return the indicators of the years the member has records in?

听起来您想获取查询结果并在更新中使用它:

It sounds like you would want take your query results and use it in your update:

http://dev.mysql.com/doc/refman/5.0/en/update.html

可能看起来像这样:

UPDATE targetTable t, sourceTable s 
SET t.y1 = s.y1, t.y2 = s.y2 -- (and so on...)
WHERE t.member = s.member AND t.year = m.year;

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