选择列值相同的列 [英] SELECT COLUMNS WHERE COLUMNS VALUE ARE SAME

问题描述

这是我的表格数据.

column_1_____column_3_____column_4_____column_5_____column_6_____column_7_____column_8 
   yes         no           yes           yes          yes          no           yes   

这里，他们只有一个数据行

我只想要那些具有 value = 'yes' 的列.

I want only that columns which has value = 'yes'.

为此哪个查询有效?

推荐答案

SQL 不是围绕列组织的.它是围绕行组织的.你可以用这样的查询做你想做的事:

SQL is not organized around columns. It is organized around rows. You can do what you want with a query like this:

select 'column1' as col
from t
where column1 = 'yes'
union all
select 'column2' as col
from t
where column2 = 'yes'
union all
. . .
union all
select 'column8' as col
from t
where column8 = 'yes';

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