如何使用选择案例在MySQL

Question

DELIMITER $$ 

CREATE 

    PROCEDURE `cheque_alert`.`SavePoData`(IN poNo VARCHAR(25),IN releaseOrderDate DATE,IN expiryDate DATE,IN enteredDateTime DATETIME,IN enteredBy VARCHAR(8) , 
    IN poItemCode VARCHAR(25),IN poItemsId CHAR(1),IN poItemDescription VARCHAR(75),IN quantity DOUBLE,IN amount DOUBLE 
    ) 

    BEGIN 
     SELECT CASE WHEN ((SELECT 1 FROM `cheque_alert`.`po_main` WHERE po_no=poNo)>0) 
     THEN   
     INSERT INTO `cheque_alert`.`po_items_details` 
      (`pomainid_id`, 
      `po_item_code`, 
      `po_items_id`, 
      `po_item_description`, 
      `quantity`, 
      `amount`) 
     VALUES ((SELECT id FROM `cheque_alert`.`po_main` WHERE po_no =poNo), 
      poItemCode,poItemsId,poItemDescription,quantity,amount) 

    ELSE   
     INSERT INTO `cheque_alert`.`po_main` 
      (`po_no`, 
      `release_order_date`, 
      `expiry_date`, 
      `entered_date_time`, 
      `entered_by`) 
     VALUES (poNo,releaseOrderDate,expiryDate,enteredDateTime,(SELECT ID FROM cheque_alert.user_login WHERE USER_ID=enteredBy)); 

     INSERT INTO `cheque_alert`.`po_items_details` 
      (`pomainid_id`, 
      `po_item_code`, 
      `po_items_id`, 
      `po_item_description`, 
      `quantity`, 
      `amount`) 
     VALUES ((SELECT LAST_INSERT_ID(), 
      poItemCode, 
      poItemsId, 
      poItemDescription, 
      quantity, 
      amount); 

    END; 
    END$$ 

DELIMITER ; 

产生错误：

Error Code : 1064

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'INTO cheque_alert . po_items_details (pomainid_id , `po_item_cod' at line 14

请让我知道这个错误我都做了些什么？

Answer 1

的IF-ELSE结构应该是这样的：

IF(some query to check something) THEN 
BEGIN 
    insert something 
END 
ELSE 
BEGIN 
    insert something 
    insert something else 
END 

同时CASE将只定义一些值，而不是整个查询工作。例如：

SELECT CASE name WHEN 'hamburger' THEN 'unhealthy' ELSE 'healthy' END 
FROM food