是否可以根据某些条件选择特定值？

Question

我想知道是否可以根据给定的行符合某些条件从myTable中选择“true”或“false”。因此，例如，如果用户在名为phone_number的列中有或没有值，我会...

select (**some magic here**) as has_phone_number from users;

结果将是一堆'true'或'false'

TIA。

Answer 1

IF (phone_number != '', true, false) as has_phone_number

甚至

phone_number != '' as has_phone_number

Answer 2

使用案例陈述。

SELECT CASE WHEN Phone IS NULL THEN FALSE ELSE TRUE END AS has_phone_number FROM users;

Answer 3

select
  phone = '' as has_phone_number
from users