MySQL的 - NULL值檢查和動態SQL存儲過程中

Question

DROP PROCEDURE IF EXISTS HaveSomeFun; 
CREATE PROCEDURE HaveSomeFun(user_id CHAR(50),house_id CHAR(50),room_id CHAR(50),fun_text TEXT,video_url CHAR(100)) 
BEGIN 
DECLARE query_full TEXT; 
SET @fields_part = 'INSERT INTO fun(FunKey,UserKey,FunBody,LastModified'; 
SET @values_part = CONCAT(') VALUES(NewBinKey(), KeyToBin(\"', user_id, '\"), \"', fun_text, '\", NOW() '); 
IF (house_id) THEN 
    SET @fields_part = CONCAT(@fields_part, ', HouseKey'); 
    SET @values_part = CONCAT(@values_part, ', KeyToBin(\'', house_id, '\')'); 
END IF; 
IF (room_id) THEN 
    SET @fields_part = CONCAT(@fields_part, ', RoomKey'); 
    SET @values_part = CONCAT(@values_part, ', KeyToBin(\'', room_id, '\')'); 
END IF; 
IF (video_url IS NOT NULL) THEN 
    SET @fields_part = CONCAT(@fields_part, ', VideoURL'); 
    SET @values_part = CONCAT(@values_part, ', "', video_url, '"'); 
END IF; 
SET query_full = CONCAT(@fields_part, @values_part, ');'); 
SET @query_full = query_full; 
PREPARE STMT FROM @query_full; 
EXECUTE STMT; 
SELECT query_full; 
END; 

而且

CALL HaveSomeFun('29B455DE-A9BC-102D-9C16-00163EEDFCFC', '', 'F82C47A8-64DE-11DF-9D7E-0026B9481364', 'Jokes apart', ''); 

將建設以下字符串變量query_full

INSERT INTO fun(FunKey,UserKey,FunBody,LastModified, VideoURL) VALUES(NewBinKey(), KeyToBin("29B455DE-A9BC-102D-9C16-00163EEDFCFC"), "Jokes apart", NOW() , ""); 

但我需要得到

INSERT INTO fun(FunKey,UserKey,FunBody,LastModified, RoomKey, VideoURL) VALUES(NewBinKey(), KeyToBin("29B455DE-A9BC-102D-9C16-00163EEDFCFC"), "Jokes apart", NOW() , KeyToBin('F82C47A8-64DE-11DF-9D7E-0026B9481364'), ""); 

東西丟失檢查IF (room_id) THEN。但是我不能強加IF (room_id IS NOT NULL) THEN，因爲它會創建KeyToBin（''）並且RoomKey是外鍵，KeyToBin（''）會產生一個無效的RoomKey。

任何想法？

Answer 1

得到了問題，就應該像

DROP PROCEDURE IF EXISTS HaveSomeFun; 
CREATE PROCEDURE HaveSomeFun(user_id CHAR(50),house_id CHAR(50),room_id CHAR(50),fun_text TEXT,video_url CHAR(100)) 
BEGIN 
DECLARE query_full TEXT; 
SET @fields_part = 'INSERT INTO fun(FunKey,UserKey,FunBody,LastModified'; 
SET @values_part = CONCAT(') VALUES(NewBinKey(), KeyToBin(\"', user_id, '\"), \"', fun_text, '\", NOW() '); 
IF (house_id != '') THEN 
    SET @fields_part = CONCAT(@fields_part, ', HouseKey'); 
    SET @values_part = CONCAT(@values_part, ', KeyToBin(\'', house_id, '\')'); 
END IF; 
IF (room_id != '') THEN 
    SET @fields_part = CONCAT(@fields_part, ', RoomKey'); 
    SET @values_part = CONCAT(@values_part, ', KeyToBin(\'', room_id, '\')'); 
END IF; 
IF (video_url IS NOT NULL) THEN 
    SET @fields_part = CONCAT(@fields_part, ', VideoURL'); 
    SET @values_part = CONCAT(@values_part, ', "', video_url, '"'); 
END IF; 
SET query_full = CONCAT(@fields_part, @values_part, ');'); 
SET @query_full = query_full; 
PREPARE STMT FROM @query_full; 
EXECUTE STMT; 
SELECT query_full; 
END;