IN語句中的案例語句

Question

我在查詢中使用了可變年齡，如下所示：

Declare @age as int 11

Select * from people p where p.age = @age

但是當我在@age上輸入0時，我想顯示10到13歲之間的所有人，因此我正在嘗試執行以下操作：

Select * 
from people p 
where p.age in( case 
                     when @age = 0 
                          then 10, 11, 12, 13
                          else @age
                     end
              )

有人可以給我點燈嗎？

Answer 1

您不需要CASE語句，只需稍微切換一下WHERE子句即可。 這應該返回相同的結果：

Select * 
from people p 
where 
( 
    @age = 0 
    AND p.age IN (10, 11, 12, 13)
)
OR
(
    @age != 0 
    AND p.age = @age
)

Answer 2

您不需要案例說明：

SELECT col1, col2, ..., coln
FROM people AS p 
WHERE (@age = 0 AND p.age BETWEEN 10 AND 13)
OR (@age <> 0 AND p.age = @age)

Answer 3

這似乎最簡單

如果業務規則發生更改，也很容易進行修改。

declare @min int
declare @max int
declare @age int

set @age = 0

if (@age = 0)
begin
   SET @min = 10
   SET @max = 13
end
else
begin
   SET @min = @age
   SET @max = @age
end 

Select * 
from people p 
where age >= @min and age <= @max

Answer 4

select *
from people
where (age between 10 and 13 and @age=0) 
or (age = @age)

Answer 5

您需要將SELECT添加到IN（）部分

Select * 
from people p 
where p.age in (SELECT case 
                     when @age = 0 
                          then 10, 11, 12, 13
                          else @age
                     end
              )