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我嘗試用存儲的SQL過程替換運行多個請求的重度Java方法。 它正在完成它的工作，但我期望性能得到更高的改進。 程序的邏輯（以及Java方法）：從表1（目的）的ID使用遊標和臨時表時MySQL存儲過程的性能問題
- 獲取列表
- 迭代列表，並從表2（記錄）字段的平均值爲每個ID
- 返回列表對ID的 /AVERAGE_VALUE
是否有手術中的任何效率問題？
DROP PROCEDURE IF EXISTS test1.getGeneralAverage;
CREATE [email protected] PROCEDURE getGeneralAverage()
BEGIN
DECLARE p_id BIGINT(20);
DECLARE exit_loop BOOLEAN;
DECLARE cur CURSOR FOR
SELECT purpose_id FROM purpose
WHERE purpose.type = 'GENERAL'
AND (SELECT COUNT(*) > 0 FROM record
WHERE record.purpose_id=purpose.purpose_id) is true;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET exit_loop = TRUE;
CREATE TEMPORARY TABLE IF NOT EXISTS general_average
(id BIGINT(20), average DOUBLE) ENGINE=memory;
TRUNCATE TABLE general_average;
OPEN cur;
average_loop: LOOP
FETCH cur INTO p_id;
INSERT INTO test1.general_average (id, average)
VALUES (p_id, (SELECT AVG(amount) FROM record
WHERE record.purpose_id=p_id));
IF exit_loop THEN
CLOSE cur;
LEAVE average_loop;
END IF;
END LOOP average_loop;
INSERT INTO test1.general_average (id, average)
VALUES (0,
(select avg(amount) from record where purpose_type='CUSTOM'));
SELECT * FROM general_average;
END