SQL SELECT - 根据条件返回布尔值

Question

基本上我正在努力做到这一点

select  u.Hostname, u.IsCustom, (u.Status = 5) as IsActive
from    SiteUrlMappings u

其中5是表示"活动"URL的int.

当然这不起作用,我的sql就像一把旧螺丝刀一样生锈.

Answer 1

您不需要CASE表达式
只是利用如何bit工作:当转换为位时,所有非零值都给出1

SELECT
    u.Hostname,
    u.IsCustom,
    ~ CAST((u.Status - 5) AS bit) AS IsActive
from    SiteUrlMappings u

Answer 2

SQL Server没有布尔数据类型.最接近的是bit

SELECT u.Hostname,
       u.IsCustom,
       CAST(CASE
              WHEN u.Status = 5 THEN 1
              ELSE 0
            END AS BIT) AS IsActive
FROM   SiteUrlMappings u  

Answer 3

你需要一个case声明,如下所示:

select  u.Hostname,
        u.IsCustom,
        convert(bit, case when u.Status = 5 then 1 else 0 end) as IsActive

from    SiteUrlMappings u

bit 尽可能接近真正的布尔值,因为您可以在SQL Server中获得

Answer 4

尝试这个：

SELECT
    u.Hostname,
    u.IsCustom,
    CASE
WHEN u.Status = 5 THEN
    1
ELSE
    0
END AS IsActive
from    SiteUrlMappings u