MySQL存儲過程中，如何插入多個變量，CONCAT

Question

基本上我有以下存儲過程：

BEGIN 
SET @query := CONCAT("SELECT *, 
sqrt( 
     (POW(a.Latitude - co.CenterLatitude, 2)* 68.1 * 68.1) + 
     (POW(a.Longitude - co.CenterLongitude, 2) * 53.1 * 53.1) 
) AS distance 
FROM table1 as r 
JOIN table2 as co ON co.field1 = r.field2 
JOIN table3 AS a ON r.field1 = a.field2 
WHERE ",rid); 

PREPARE stmt FROM @query; 
EXECUTE stmt; 
DEALLOCATE PREPARE stmt; 

END 

它具有以下經過：

IN rid varchar(500), lat double, lon double 

但我需要通過在經度和緯度變量。我試圖設置它們，然後將它們添加到查詢中，但它不能識別它們。這是我正在嘗試做哪些不成功：

BEGIN 
    SET @lat := lat; 
    SET @lon := lon; 
    SET @query := CONCAT("SELECT *, 
    sqrt( 
      (POW(a.Latitude - @lat, 2)* 68.1 * 68.1) + 
      (POW(a.Longitude - @lon, 2) * 53.1 * 53.1) 
    ) AS distance 
    FROM table1 as r 
    JOIN table2 as co ON co.field1 = r.field2 
    JOIN table3 AS a ON r.field1 = a.field2 
    WHERE ",rid); 

    PREPARE stmt FROM @query; 
    EXECUTE stmt; 
    DEALLOCATE PREPARE stmt; 

    END 

我不知道如何做到這一點。有沒有人有什麼建議？先謝謝你！！

Answer 1

您可以在準備好的語句中放置?佔位符，然後在執行時提供值。

SET @query := CONCAT("SELECT *, 
sqrt( 
     (POW(a.Latitude - ?, 2)* 68.1 * 68.1) + 
     (POW(a.Longitude - ?, 2) * 53.1 * 53.1) 
) AS distance 
FROM table1 as r 
JOIN table2 as co ON co.field1 = r.field2 
JOIN table3 AS a ON r.field1 = a.field2 
WHERE ",rid); 
PREPARE stmt FROM @query; 
EXECUTE stmt USING @lat, @lon; 

Answer 2

Barmar的答案會是我的首選解決方案，但給我的就是我最初的註釋的一個例子是在暗示......

BEGIN 
SET @query := CONCAT("SELECT *, 
sqrt( 
     (POW(a.Latitude - ", lat, ", 2)* 68.1 * 68.1) + 
     (POW(a.Longitude - ", lon, ", 2) * 53.1 * 53.1) 
) AS distance 
FROM table1 as r 
JOIN table2 as co ON co.field1 = r.field2 
JOIN table3 AS a ON r.field1 = a.field2 
WHERE ",rid); 

PREPARE stmt FROM @query; 
EXECUTE stmt; 
DEALLOCATE PREPARE stmt; 

END