错误发生在另一个设置上，而不是我的："Table is specified twice, both as a target for 'UPDATE' and as a separate source for data in MySQL"

Question

我的问题是link下面的问题：

就我而言，下面的触发器在我的本地设置上运行良好（LAMPP on Ubuntu）：

-- trigger to increment balance on posting of a new bill
DELIMITER
    //
CREATE TRIGGER trig_increment_balance_new_bill AFTER INSERT ON
    tbl_bill FOR EACH ROW
BEGIN
    DECLARE
        vBillAmount DOUBLE ;
    SELECT NEW
        .amount
    INTO vBillAmount ;
UPDATE
    tbl_client T
SET
    balance = balance + vBillAmount
WHERE
    id =(
    SELECT
        id
    FROM
        tbl_client C
    WHERE NEW
        .metreNo = C.metreNo
    LIMIT 1
) ;
END ; //
DELIMITER
    ;

但是，我的协作者的设置（XAMPP 在 Windows 上）时出现以下错误重新创建相同的代码并进行测试。

SQLSTATE[HY000]: General error: 1093 Table 'T' is specified twice, both as a target for 'UPDATE' and as a separate source for data

我以为是严格模式有关，结果发现是严格模式开启； 'STRICT_ALL_TABLES' 就我而言。为什么他的设置会出错，而我的却不会？我知道上面 link 中提供的解决方案可能会解决此错误，但问题是为什么错误会选择性地发生？

Answer 1

不需要子查询，直接把条件放在WHERE子句中即可。您也不需要 vBillAmount 变量。

CREATE TRIGGER trig_increment_balance_new_bill AFTER INSERT ON tbl_bill 
FOR EACH ROW
    UPDATE tbl_client c 
    SET c.balance = c.balance + NEW.amount 
    WHERE c.metreNo = NEW.metreNo
    LIMT 1;

错误发生在另一个设置上，而不是我的："Table is specified twice, both as a target for 'UPDATE' and as a separate source for data in MySQL"

The error occurs on another setup, not on mine: "Table is specified twice, both as a target for 'UPDATE' and as a separate source for data in MySQL"

mysql

xampp

lampp