如何在sqlserver中使用case Statemet获取Null值？

本文介绍了如何在sqlserver中使用case Statemet获取Null值？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 我想使用case语句获取null值。 我的sql查询如下 选择 UserID，ProcessDate，Leave =（ case 当 firsthalf = ' PR' 和 secondhalf = ' PR' 然后 ' 0' 何时 firsthalf = ' WO' 和 secondhalf = ' WO' 然后 ' 0' 当 firsthalf = ' AB' 和 secondhalf = ' AB' 然后 ' 1' when firsthalf null 和 secondhalf null 然后 ' 1' firsthalf = ' PR' 和 secondhalf = ' AB' 然后 ' 0.5' 何时 firsthalf = ' AB' 和 secondhalf = ' PR' 然后 ' 0.5' when firsthalf = ' IN' 和 secondhalf null 然后 ' 0.5' firsthalf = ' IN' 和 secondhalf = ' AB' 然后 ' 0.5' 何时 firsthalf = ' IN' 和 secondhalf = ' Out' 然后 ' 0.5' firsthalf = ' Out' 和 secondhalf = ' IN' 然后 ' 0.5' end ），d atename（月，processdate） as 月份，datepart（yyyy，processdate） as 年 来自 Accounts_DailyAttendance 其中 UserID = 1003 和 datename（ month，processdate）= ' March' 和 datepart（yyyy，processdate）= ' 2014' 和 firsthalf<> ' PR' 和 secondhalf<> ; ' PR' 和 firsthalf<> ; ' WO' 和 secondhalf<> ; ' WO' 当我运行上面的sql查询时，没有输出null值。 所以我想要null值数据也可以在生物识别条目中获得processdate。 请帮助我在上面的sql查询中犯了什么错误。解决方案 CASE WHEN firsthalf IS NULL AND secondhalf IS NULL 然后 NULL END 当然，您可以使用除AND之外的任何其他逻辑运算符 - 这取决于您的需求。 I want to get the null value output using case statement. My sql query as followsselect UserID, ProcessDate,Leave=( case when firsthalf = 'PR' and secondhalf = 'PR' then '0' when firsthalf = 'WO' and secondhalf = 'WO' then '0' when firsthalf = 'AB' and secondhalf = 'AB' then '1' when firsthalf is null and secondhalf is null then '1' when firsthalf = 'PR' and secondhalf = 'AB' then '0.5' when firsthalf = 'AB' and secondhalf = 'PR' then '0.5' when firsthalf = 'IN' and secondhalf is null then '0.5' when firsthalf = 'IN' and secondhalf = 'AB' then '0.5' when firsthalf = 'IN' and secondhalf = 'Out' then '0.5' when firsthalf = 'Out' and secondhalf = 'IN' then '0.5' end),datename(month,processdate) as Months,datepart(yyyy,processdate) as Years from Accounts_DailyAttendance where UserID=1003 and datename(month,processdate) = 'March' and datepart(yyyy,processdate)= '2014' and firsthalf <> 'PR' and secondhalf <> 'PR' and firsthalf <> 'WO' and secondhalf <> 'WO'When i run the above sql query null value output is not came.so i want null value data also get processdate in biometric entry. please help me what is the mistake i made in my above sql query. 解决方案 CASE WHEN firsthalf IS NULL AND secondhalf IS NULL then NULLENDOf course you can use any other logical operator than AND - it depends on your needs. 这篇关于如何在sqlserver中使用case Statemet获取Null值？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！