SQL(如果小于和大于 WHERE 子句)

Question

我想在 WHERE 或 agregat 函数 IIF 或其他类似工作的东西中使用 CASE WHEN：

@iKapacitet
AS
SELECT ID, Name
FROM Private-Accommodation
WHERE [Private-Accommodation].[Otok]='Rab'AND 
IIF(@iKapacitet = 1,[Private-Accommodation].[maxPersons] < 3,
IIF(@iKapacitet = 2, [Private-Accommodation].[maxPersons] < 3 AND [Private-Accommodation].[maxPersons] > 5, 
[Private-Accommodation].[maxPersons] BETWEEN 4 AND 6))
ORDER BY [Private-Accommodation].[RedniBr]

如果使用 CASE 更容易：

CASE @iKapacitet 
WHEN 1 THEN (CASE [Private-Accommodation].[maxBrOsoba] WHEN < 3)
WHEN 2 THEN (CASE [Private-Accommodation].[maxBrOsoba] WHEN < 3 AND > 5)
WHEN 3 THEN (CASE [Private-Accommodation].[maxPersons] BETWEEN 4 AND 6)
END

Answer 1

将

if/case 逻辑保留在where子句之外通常更清楚。 您可以考虑：

WHERE [Private-Accommodation].[Otok] = 'Rab' AND 
      ((@iKapacitet = 1 AND [Private-Accommodation].[maxPersons] < 3) OR
       (@iKapacitet = 2 AND [Private-Accommodation].[maxPersons] < 3) AND [Private-Accommodation].[maxPersons] > 5) OR
       (@iKapacitet NOT IN (1, 2) AND [Private-Accommodation].[maxPersons] BETWEEN 4 AND 6)
      )