點存在於圓圈

Question

讓我們考慮(x,y)是一個點，然後做一個radius的一些值r。如果假設我有一個點(a,b)，我需要檢查(a,b)是否在以(x,y)爲中心的圓內。

如何在SQL Server中實現此目的？

Answer 1

測試數據

DECLARE @t TABLE (x NUMERIC(10,2), y NUMERIC(10,2), radius NUMERIC(10,2)) 
INSERT INTO @t 
VALUES (3.5,3.5, 5.5),(20.5,20.5, 10.5), (30.5,30.5, 20.5) 

查詢

DECLARE @p1 NUMERIC(10,2) = 5.5 --<-- Point to check 
DECLARE @p2 NUMERIC(10,2) = 5.5 


SELECT *, CASE WHEN POWER(@p1 - x, 2) + POWER(@p2 - y, 2) <= POWER(radius, 2) 
      THEN 'Inside The Circle' 
      WHEN POWER(@p1 - x, 2) + POWER(@p2 - y, 2) > POWER(radius, 2) 
      THEN 'Outside the Circle' END [Inside/Outside] 
FROM @t 

結果集

╔═══════╦═══════╦════════╦════════════════════╗ 
║ x ║ y ║ radius ║ Inside/Outside ║ 
╠═══════╬═══════╬════════╬════════════════════╣ 
║ 3.50 ║ 3.50 ║ 5.50 ║ Inside The Circle ║ 
║ 20.50 ║ 20.50 ║ 10.50 ║ Outside the Circle ║ 
║ 30.50 ║ 30.50 ║ 20.50 ║ Outside the Circle ║ 
╚═══════╩═══════╩════════╩════════════════════╝ 

隨着問題被關閉，再也噸添加其他的回答，所以我編輯此使用SQL Server Geometry類型爲包括溶液... [使用如上相同的數據點，加上一個精確演示圓上]

Declare @t TABLE 
    (x NUMERIC(10,2), y NUMERIC(10,2), 
    radius NUMERIC(10,2)) 
Insert @t 
Values (3.5,3.5, 5.5),(20.5,20.5, 10.5), 
     (30.5,30.5, 20.5), (-5.5, 5.5, 11.0) 

-- -------------------------- 
Declare @pX float = 5.5  
Declare @pY float = 5.5 
Declare @c geometry; 
Declare @p geometry; 
Select x, y, radius, 
     (geometry::Point(X, Y, 0)).STDistance(geometry::Point(@pX, @pY, 0)) 
From @T 
Where (geometry::Point(X, Y, 0)).STDistance(geometry::Point(@pX, @pY, 0)) > radius