Question

我有一个带有客户ID的表，然后是30+列，带有0或1.我想在第一列中返回客户ID，然后在第二列中返回客户ID的名称列＆lt;＆gt; 0。表的内容如下：

CustomerID, Product1, product2, product3, ...
123456         0          1          1

我想要回归：

123456, Product2
123456. Product3
...

我目前使用的代码......

Answer 1

听起来您需要重新设计数据库以更好地满足您的要求。

鉴于目前的情况应该能够做到以下几点：

SELECT CustomerID,'Product1' FROM yourtable WHERE product1<>0
UNION 
SELECT CustomerID,'Product2' FROM yourtable WHERE product2<>0
UNION 
SELECT CustomerID,'Product3' FROM yourtable WHERE product3<>0

等等。

Answer 2

你必须把桌子弄掉，这将是丑陋的，但可以简单地通过使用足够数量的工会来完成，就像这样;

SELECT CustomerId, 'Product1' as product FROM mytable WHERE product1 != 0
UNION ALL
SELECT CustomerId, 'Product2' as product FROM mytable WHERE product2 != 0
UNION ALL
SELECT CustomerId, 'Product3' as product FROM mytable WHERE product3 != 0
UNION ALL
   ....
UNION ALL
SELECT CustomerId, 'Product31' as product FROM mytable WHERE product31 != 0
UNION ALL
SELECT CustomerId, 'Product32' as product FROM mytable WHERE product32 != 0;

SQL：需要客户ID，然后是所有不是= 0的列名

2 个答案: