MySQL的觸發更新，如果ELSE插入

Question

我試圖做一個觸發INSERT INTO在的checkedOutBy的更新後表後裝備表。

它給了我一個Error 1064在第7,10行和其他人，因爲我已經隨機改變了事情，希望它能以某種方式神奇地工作。

DELIMITER $$ 

CREATE TRIGGER moveToHistory AFTER UPDATE ON equip 
FOR EACH ROW 
BEGIN 

IF NEW.checkedOutBy <> Old.checkedOutBy 
BEGIN 

IF OLD.checkedOutBy IS NOT NULL AND NEW.checkedOutBy IS NULL THEN 
    INSERT INTO equipmentHistory(assetId, operation, createdBy, creationDate) 
    VALUES(new.assetId, 'CheckIn', eid, Date(sysdate())) 
    NEW.status = 'CheckedIn'; 
ELSE IF OLD.checkedOutBy IS NULL AND NEW.checkedOutBy IS NOT NULL THEN 
    INSERT INTO equipmentHistory(assetId, operation, createdBy, creationDate) 
    VALUES(new.assetId, 'Checkout', eid, Date(sysdate())) 
    NEW.status = 'CheckedOut'; 
END IF 
END 
END$$ 

DELIMITER ; 

Answer 1

下面是正確的語法，觸發if - elseif

DELIMITER $$ 
CREATE TRIGGER moveToHistory AFTER UPDATE ON equip 
FOR EACH ROW 
BEGIN 
IF NEW.checkedOutBy <> Old.checkedOutBy then 
    IF OLD.checkedOutBy IS NOT NULL AND NEW.checkedOutBy IS NULL THEN 
     INSERT INTO equipmentHistory(assetId, operation, createdBy, creationDate) 
     VALUES(new.assetId, 'CheckIn', eid, curdate()); 
    ELSEIF OLD.checkedOutBy IS NULL AND NEW.checkedOutBy IS NOT NULL THEN 
     INSERT INTO equipmentHistory(assetId, operation, createdBy, creationDate) 
     VALUES(new.assetId, 'Checkout', eid, curdate()); 
    END IF; 
END IF ; 
END;$$ 

DELIMITER ; 

另外請注意，我已刪除NEW.status = 'CheckedIn';和NEW.status = 'CheckedOut';，這些沒有意義，當你嘗試使用after update觸發

Answer 2

設置

請試試

DELIMITER // 

CREATE TRIGGER moveToHistory AFTER UPDATE ON equip 
FOR EACH ROW 
BEGIN 

IF NEW.checkedOutBy != Old.checkedOutBy 
BEGIN 

IF OLD.checkedOutBy IS NOT NULL AND NEW.checkedOutBy IS NULL THEN 
    INSERT INTO equipmentHistory(assetId, operation, createdBy,creationDate) 
    VALUES(new.assetId, 'CheckIn', eid, Date(sysdate())) 
NEW.status = 'CheckedIn'; 
ELSE IF OLD.checkedOutBy IS NULL AND NEW.checkedOutBy IS NOT NULL THEN 
INSERT INTO equipmentHistory(assetId, operation, createdBy, creationDate) 
VALUES(new.assetId, 'Checkout', eid, Date(sysdate())) 
NEW.status = 'CheckedOut'; 
END IF 
END 
END 
// 
DELIMITER ;