MySQL的追加與功能

Question

整數返回0我已經在mysql中創建了這個功能，我想與像(1,0,-2,-1)而是它給結果cocated值導致0

DROP Function IF EXISTS get_preorder_status; 
DELIMITER $$ 
CREATE Function get_preorder_status(loc_pre_order_id int) RETURNS INT(10) 
BEGIN  
DECLARE all_status CHAR(10) DEFAULT ''; 
DECLARE temp_status INT(2); 
DECLARE n INT DEFAULT 0; 
DECLARE i INT DEFAULT 0; 

SELECT count(*) into n 
FROM pre_order_detail 
WHERE pre_order_id = loc_pre_order_id; 

WHILE i<n DO 
SELECT customer_response_status into temp_status 
FROM pre_order_detail 
WHERE pre_order_id = loc_pre_order_id LIMIT i,1; 
SET all_status = CONCAT(all_status,', ',CAST(temp_status AS CHAR)); 
SET i = i + 1; 
END WHILE;` 

RETURN all_status; 
END$$ 
DELIMITER ; 

all_status是char類型的變量，但temp_status是INT字符我想CONCAT最終結果與逗號在一個字符串類型值的整數值saparated

請幫

Answer 1

你的函數返回一個int。嘗試讓它返回一個字符類型。

換句話說，字符串在返回時被轉換爲int。

邏輯可以更簡單地寫爲：

SELECT group_concat(customer_response_status) into temp_status 
FROM pre_order_detail 
WHERE pre_order_id = loc_pre_order_id ; 

沒有必要爲一個循環。