在SQL

Question

我有以下查询，其中输出称呼为先生/女士

的成员的数量和百分比

我想将结果重命名为'男'而不是'先生'和女性，而不是'女士'。

这可能是一个相当简单的案例，但无法让它发挥作用......

SELECT AspNetUsers.Salutation AS Sex, COUNT(AspNetUsers.Salutation) as Total, 
CAST(ROUND((COUNT(AspNetUsers.Salutation)* 100.0 / (SELECT COUNT(*) FROM Member, AspNetUsers WHERE Member.AspNetUserId = AspNetUsers.Id)),1) AS NUMERIC(36,1)) AS Percentage
FROM Member, AspNetUsers
WHERE Member.AspNetUserId=AspNetUsers.Id
GROUP BY Salutation

Answer 1

您绝对认为它是一个简单的案例表达式，但您还需要按相同的案例表达式进行分组。

SELECT 
    CASE 
      WHEN AspNetUsers.Salutation = 'Mr' THEN 'Male' 
      WHEN AspNetUsers.Salutation = 'Ms' THEN 'Female' 
      ELSE 'Other'  -- this is of course optional
    END AS Sex, 
    COUNT(AspNetUsers.Salutation) as Total, 
    CAST(ROUND((COUNT(AspNetUsers.Salutation)* 100.0 / (SELECT COUNT(*) FROM Member JOIN AspNetUsers ON Member.AspNetUserId = AspNetUsers.Id)),1) AS NUMERIC(36,1)) AS Percentage
FROM Member
JOIN AspNetUsers ON Member.AspNetUserId = AspNetUsers.Id
GROUP BY 
  CASE 
    WHEN AspNetUsers.Salutation = 'Mr' THEN 'Male' 
    WHEN AspNetUsers.Salutation = 'Ms' THEN 'Female' 
    ELSE 'Other'   -- this is of course optional
  END;

通过使用公用表表达式不必重复case表达式和窗口计数而不是子查询，可以改进查询，但我会留给你。