MySql存储过程，如何用CONCAT插入多个变量

Question

基本上我有以下存储过程:

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

它有以下传递:

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

但是我需要传入纬度和经度变量。我试过设置它们然后将它们添加到查询中但它无法识别它们。这是我正在尝试做的，但没有成功:

    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

我不确定如何完成此操作。有没有人有什么建议？提前致谢!!

Answer 1

您可以将 ? 占位符放在准备好的语句中，然后在执行时提供值。

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;