根据postgres中其他列的值创建一个新列

Question

我有什么

customer_id
   1
   2 
   2
   1
   3

我想要的是（对于所有客户ID＆1，我希望将其标记为有效，其余客户ID在新列中无效＆＃34; warining_customer_id＆＃34;

customer_id    warining_customer_id
   1             Valid
   2             Invalid
   2             Invalid
   1             Valid
   3             Invalid

Answer 1

这是一个例子

SELECT   customer.customer_id AS customer_id,
         CASE WHEN customer.customer_id = 1 THEN 'Valid' ELSE 'Invalid' END
             AS warning_customer_id
  FROM   (SELECT   1 AS customer_id FROM DUAL
          UNION ALL
          SELECT   2 AS customer_id FROM DUAL) customer