如何在 MySQL 中找到下一个星期六

Question

我有触发器和一个存储过程（所以 SP 在触发器运行时运行）。我需要一个函数来找到下一个星期六放入 SP。

所以让我们说，今天是星期三（2015-7-22）。如果我的触发器今天运行，其中的 SP 必须找到下一个星期六 (2015-7-25)。

另外，即使是星期六，但时间早于晚上 9.30，它也必须找到当天。晚上 9.30 之后，它必须在下周六返回。

我想把我的整个触发器和 sp 放在这里，但我不想在这里拥挤。我只需要想法，谢谢。

编辑：

感谢 oNaye，我编写了以下代码：

CREATE DEFINER=`root`@`localhost` PROCEDURE `newGuess`(
IN `muserID` INT, 
IN `numm1` INT, 
IN `numm2` INT, 
IN `numm3` INT, 
IN `numm4` INT, 
IN `numm5` INT, 
IN `numm6` INT)
    begin
set @today = (select weekday(curdate())+1); /*monday is the first day in here*/
if @today<6 or @today=7 then /*it is NOT saturday*/
    set @nextSaturday = (SELECT DATE_ADD(NOW(),INTERVAL IF(WEEKDAY(NOW())>=5,(6-WEEKDAY(NOW())),(5-WEEKDAY(NOW()))) DAY));
end if;
if @today = 6 then /* it is saturday */
    set @current_time = (select curtime());
    set @nextSaturday = (SELECT DATE_ADD(NOW(),INTERVAL IF(WEEKDAY(NOW())>=5,(6-WEEKDAY(NOW())),(5-WEEKDAY(NOW()))) DAY));
    if @current_time < CAST('21:30:00' AS time) then
        set @nextSaturday = curdate();
    end if;
    if @current_time >=CAST('21:30:00' AS time) then
        set @nextSaturday = curdate()+INTERVAL 1 WEEK;
    end if;
end if;
insert into guessesTBL (userID,num1,num2,num3,num4,num5,num6,current__datetime,draw_date) values (muserID,numm1,numm2,numm3,numm4,numm5,numm6,NOW(),@nextSaturday);

end

它现在起作用了。解决了。

Answer 1

您可以使用WEEKDAY和DATE_ADD函数来计算下一个工作日的到来。

在这里你必须做的：

SELECT 
  DATE_ADD(NOW(),INTERVAL IF(WEEKDAY(NOW())>=5,
                             (6-WEEKDAY(NOW())),
                             (5-WEEKDAY(NOW()))) DAY);

查询含义：

随着DATE_ADD您将添加参数之间的间隔NOW()假设我平日周六是和一个条件5，你必须评估是否NOW()大于5或等于，你有休息它6（周日），如果NOW()不是少5，你必须休息吧5与NOW().

测试：

mysql> SELECT NOW();
+---------------------+
| NOW()               |
+---------------------+
| 2015-07-22 07:51:33 |
+---------------------+
1 row in set (0.00 sec)

mysql> SELECT DATE_ADD(NOW(),INTERVAL IF(WEEKDAY(NOW())>=5,(6-WEEKDAY(NOW())),(5-WEEKDAY(NOW()))) DAY);
+------------------------------------------------------------------------------------------+
| DATE_ADD(NOW(),INTERVAL IF(WEEKDAY(NOW())>=5,(6-WEEKDAY(NOW())),(5-WEEKDAY(NOW()))) DAY) |
+------------------------------------------------------------------------------------------+
| 2015-07-25 07:51:34                                                                      |
+------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> 

编辑：

如果您需要计算得到下一个星期六（如果实际星期六是晚上 9:30）：

新语法：

SET @ACTUAL_DATE=NOW();
SET @NEXT_SATURDAY=DATE_ADD(@ACTUAL_DATE,INTERVAL IF(WEEKDAY(@ACTUAL_DATE)=5 && TIME(@ACTUAL_DATE)>'21:30:00',
                                            7,
                                            IF(WEEKDAY(@ACTUAL_DATE)>=5,
                                                (6-WEEKDAY(@ACTUAL_DATE)),
                                                (5-WEEKDAY(@ACTUAL_DATE)))) 
                                        DAY);

今天测试：

mysql> SET @ACTUAL_DATE=NOW();
Query OK, 0 rows affected (0.01 sec)

mysql> SET @NEXT_SATURDAY=DATE_ADD(@ACTUAL_DATE,INTERVAL IF(WEEKDAY(@ACTUAL_DATE)=5 && TIME(@ACTUAL_DATE)>'21:30:00',
    -> 7,
    -> IF(WEEKDAY(@ACTUAL_DATE)>=5,
    -> (6-WEEKDAY(@ACTUAL_DATE)),
    -> (5-WEEKDAY(@ACTUAL_DATE)))) 
    -> DAY);
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT @NEXT_SATURDAY;
+---------------------+
| @NEXT_SATURDAY      |
+---------------------+
| 2015-07-25 21:30:01 |
+---------------------+
1 row in set (0.00 sec)

mysql> 

但如果我们在July 25th at 21:30:01（星期六）：

mysql> SET @ACTUAL_DATE='2015-07-25 21:30:01';
Query OK, 0 rows affected (0.00 sec)

mysql> SET @NEXT_SATURDAY=DATE_ADD(@ACTUAL_DATE,INTERVAL IF(WEEKDAY(@ACTUAL_DATE)=5 && TIME(@ACTUAL_DATE)>'21:30:00',
    -> 7,
    -> IF(WEEKDAY(@ACTUAL_DATE)>=5,
    -> (6-WEEKDAY(@ACTUAL_DATE)),
    -> (5-WEEKDAY(@ACTUAL_DATE)))) 
    -> DAY);
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT @NEXT_SATURDAY;
+---------------------+
| @NEXT_SATURDAY      |
+---------------------+
| 2015-08-01 21:30:01 |
+---------------------+
1 row in set (0.00 sec)