Question

我有一个列，我们存储所选日期值的总和..例如，我有固定的日期值

1  Sunday
2  Monday
4  Tuesday
8  Wednesday
16 Thursday
32 Friday
64 Saturday

在我的专栏中我得到了12，所以很清楚用户选择了(4)Tuesday+(8)Wednesday=12

现在我有106个逻辑我可以写出来找出它的天数组合吗？

Answer 1

SELECT *,
  ( (SelDates &  1) =  1) AS IsSun,
  ( (SelDates &  2) =  2) AS IsMon,
  ( (SelDates &  4) =  4) AS IsTue,
  ( (SelDates &  8) =  8) AS IsWed,
  ( (SelDates & 16) = 16) AS IsThu,
  ( (SelDates & 32) = 32) AS IsFri,
  ( (SelDates & 64) = 64) AS IsSat
FROM <table>

这应该适用于MySQL和SQL-Server，因为它们都支持＆amp;按位AND运算符。

Answer 2

您可以像这样检查它（MS SQL，按位AND）：

SELECT 
CASE WHEN (daySum & 1) = 1 THEN 'IsMonday' 
CASE WHEN (daySum & 2) = 2 THEN 'IsTuesDay' 
CASE WHEN (daySum & 4) = 4 THEN 'IsWednesDay' 
... etc ...
END FROM MyTable

Answer 3

在MySQL中，您可以直接使用BIN函数

获取位图

SELECT LPAD(BIN(106), 7,'0') --> 1101010

MSB是星期六，LSB星期日

如何找到值是所有天的总和

3 个答案: