mysql 去掉末尾字符串

-- 使用 RIGHT() 函数
UPDATE users SET email = RIGHT(email, LENGTH(email) - LENGTH(REPLACE(email, ' ', '')));

-- 使用 SUBSTRING() 函数
UPDATE users SET email = SUBSTRING(email, 1, LENGTH(email) - LENGTH(REPLACE(email, ' ', '')));

UPDATE users SET email = SUBSTRING(email, 1, LENGTH(email) - LENGTH(REPLACE(REPLACE(email, ' ', ''), CHAR(10), '')));

DELIMITER //

CREATE FUNCTION RemoveTrailingChars(str VARCHAR(255), char CHAR(1))
RETURNS VARCHAR(255)
DETERMINISTIC
BEGIN
    DECLARE len INT;
    DECLARE result VARCHAR(255);
    SET len = LENGTH(str);
    SET result = str;
    
    WHILE RIGHT(result, 1) = char DO
        SET result = SUBSTRING(result, 1, len - 1);
        SET len = LENGTH(result);
    END WHILE;
    
    RETURN result;
END //

DELIMITER ;

UPDATE users SET email = RemoveTrailingChars(email, ' ');