Question

我需要找出给定月份的第一个/第二个/第三个/第四个/最后一个工作日我还需要周末来安排复发。

我可以找到第一个工作日：

SELECT CASE Dayofweek('2012-11-04') 
         WHEN 1 THEN Date_add('2012-11-04', INTERVAL 1 DAY) 
         WHEN 7 THEN Date_add('2012-11-04', INTERVAL 2 DAY) 
         ELSE '2012-11-04' 
       END AS dateStart

同样，我需要得到第二个等等。

Answer 1

在SQL Server上，DATEPART(dw, your_date)会告诉您它是否是周末。通常1表示星期六，7表示星期日，但它可以根据服务器配置而改变。阅读有关datepart函数的信息，了解它的工作原理

Answer 2

MySQL中的

：

CREATE TABLE calendar
(
  date date not null,
  isBus bit
);
ALTER TABLE calendar
ADD CONSTRAINT PK_calendar
PRIMARY KEY(date);


INSERT INTO calendar VALUES ('2012-10-01', 1);
INSERT INTO calendar VALUES ('2012-10-02', 1);
INSERT INTO calendar VALUES ('2012-10-03', 1);
INSERT INTO calendar VALUES ('2012-10-04', 1);
INSERT INTO calendar VALUES ('2012-10-05', 1);
INSERT INTO calendar VALUES ('2012-10-06', 0);
INSERT INTO calendar VALUES ('2012-10-07', 0);
INSERT INTO calendar VALUES ('2012-10-08', 1);
INSERT INTO calendar VALUES ('2012-10-09', 1);
INSERT INTO calendar VALUES ('2012-10-10', 1);
INSERT INTO calendar VALUES ('2012-10-11', 1);
INSERT INTO calendar VALUES ('2012-10-12', 1);
INSERT INTO calendar VALUES ('2012-10-13', 0);
INSERT INTO calendar VALUES ('2012-10-14', 0);
INSERT INTO calendar VALUES ('2012-10-15', 1);
INSERT INTO calendar VALUES ('2012-10-16', 1);
INSERT INTO calendar VALUES ('2012-10-17', 1);
INSERT INTO calendar VALUES ('2012-10-18', 1);
INSERT INTO calendar VALUES ('2012-10-19', 1);
INSERT INTO calendar VALUES ('2012-10-20', 0);
INSERT INTO calendar VALUES ('2012-10-21', 0);
INSERT INTO calendar VALUES ('2012-10-22', 1);
INSERT INTO calendar VALUES ('2012-10-23', 1);
INSERT INTO calendar VALUES ('2012-10-24', 1);
INSERT INTO calendar VALUES ('2012-10-25', 1);
INSERT INTO calendar VALUES ('2012-10-26', 1);
INSERT INTO calendar VALUES ('2012-10-27', 0);
INSERT INTO calendar VALUES ('2012-10-28', 0);
INSERT INTO calendar VALUES ('2012-10-29', 1);
INSERT INTO calendar VALUES ('2012-10-30', 1);
INSERT INTO calendar VALUES ('2012-10-31', 1);
INSERT INTO calendar VALUES ('2012-11-01', 1);
INSERT INTO calendar VALUES ('2012-11-02', 1);
INSERT INTO calendar VALUES ('2012-11-03', 0);
INSERT INTO calendar VALUES ('2012-11-04', 0);
INSERT INTO calendar VALUES ('2012-11-05', 1);
INSERT INTO calendar VALUES ('2012-11-06', 1);
INSERT INTO calendar VALUES ('2012-11-07', 1);
INSERT INTO calendar VALUES ('2012-11-08', 1);
INSERT INTO calendar VALUES ('2012-11-09', 1);
INSERT INTO calendar VALUES ('2012-11-10', 0);
INSERT INTO calendar VALUES ('2012-11-11', 0);
INSERT INTO calendar VALUES ('2012-11-12', 1);
INSERT INTO calendar VALUES ('2012-11-13', 1);
INSERT INTO calendar VALUES ('2012-11-14', 1);
INSERT INTO calendar VALUES ('2012-11-15', 1);
INSERT INTO calendar VALUES ('2012-11-16', 1);
INSERT INTO calendar VALUES ('2012-11-17', 0);
INSERT INTO calendar VALUES ('2012-11-18', 0);
INSERT INTO calendar VALUES ('2012-11-19', 1);
INSERT INTO calendar VALUES ('2012-11-20', 1);
INSERT INTO calendar VALUES ('2012-11-21', 1);
INSERT INTO calendar VALUES ('2012-11-22', 1);
INSERT INTO calendar VALUES ('2012-11-23', 1);
INSERT INTO calendar VALUES ('2012-11-24', 0);
INSERT INTO calendar VALUES ('2012-11-25', 0);
INSERT INTO calendar VALUES ('2012-11-26', 1);
INSERT INTO calendar VALUES ('2012-11-27', 1);
INSERT INTO calendar VALUES ('2012-11-28', 1);
INSERT INTO calendar VALUES ('2012-11-29', 1);
INSERT INTO calendar VALUES ('2012-11-30', 1);

然后在10月份获得所有星期四（5）：

select @rowid:=@rowid+1, calendar.* from calendar, (SELECT @rowid:=0) as init 
where dayofweek(date) = 5
and month(date) = 10
order by date;

获得10月的第二个星期四：

select * from
(select @rowid:=@rowid+1 as seqNo, calendar.* from calendar, (SELECT @rowid:=0) as init 
where dayofweek(date) = 5
and month(date) = 10
order by date) x
where seqNo = 2;

在SQL中计算给定月份的工作日

2 个答案: