mariadb - 使用联合并将列放入变量时出错

Question

我在 Ubuntu 上使用 Mariadb (10.5.12-MariaDB-1build1)。

我在表上创建了一个插入触发器；使用联合语句检查以前的记录。它在以前的版本（10.3.31-MariaDB-0ubuntu.20.04.1）中工作正常，但在这个版本中抛出错误

我已经简化了陈述

 SET @ID = '';

工会在几张桌子上，但我把它减少到两个

SELECT id FROM table1 
union 
SELECT id 
 INTO @ID 
FROM table2;

给我这个错误

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'FROM table2 at line 'line number'

显然，如果我评论 INTO 子句，那很好。

所以我想问题出在INTO。我想更具体地说是进入的位置。因为单个 select 语句没有给出任何错误。

我将检查文档以了解我做错了什么。

---

@Barmar 这是实际的代码

DELIMITER ;;
/*!50003 CREATE*/ /*!50017 DEFINER=`root`@`localhost`*/ /*!50003 TRIGGER CRPInsertTrigger
BEFORE INSERT ON CRP
FOR EACH ROW
BEGIN
    SET @msg = '';
    SET @tire = @ID = @Name = '';

    SELECT 'coMem' `tire`, coMemID `ID`, coMemName `Name` FROM coMem 
    WHERE institute = NEW.institute and registration = NEW.registration and bookNo = NEW.bookNo
    union
    SELECT 'commercialMem' `tire`, commercialMemID `ID`, commercialMemName `Name` FROM commercialMem 
    WHERE institute = NEW.institute and registration = NEW.registration and bookNo = NEW.bookNo
    union
    SELECT 'communityGeneralMem' `tire`, communityGeneralMemID `ID`, communityGeneralMemName `Name` FROM communityGeneralMem 
    WHERE institute = NEW.institute and registration = NEW.registration and bookNo = NEW.bookNo
    union
    SELECT 'CRP' `tire`, CRPID `ID`, CRPName `Name` FROM CRP 
    WHERE institute = NEW.institute and registration = NEW.registration and bookNo = NEW.bookNo
    union
    SELECT 'lsoMem' `tire`, lsoMemID `ID`, lsoMemName `Name` FROM lsoMem 
    WHERE institute = NEW.institute and registration = NEW.registration and bookNo = NEW.bookNo
    union
    SELECT 'voMem' `tire`, voMemID `ID`, voMemName `Name` 
    INTO @tire, @ID, @Name FROM voMem 
    WHERE institute = NEW.institute and registration = NEW.registration and bookNo = NEW.bookNo;

    IF @Name != '' THEN
    SET @msg = CONCAT('Error: Duplicate in registration found: ', CAST(NEW.registration AS CHAR CHARACTER SET utf8) COLLATE utf8_bin);
    SET @msg = CONCAT(@msg, '(', @tire, 'ID:',CAST(@ID AS CHAR CHARACTER SET utf8) COLLATE utf8_bin);
    SET @msg = CONCAT(@msg, ', Name:', CAST(@Name AS CHAR CHARACTER SET utf8) COLLATE utf8_bin, ')');
    SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = @msg;
    END IF;
END */;;
DELIMITER ;