SQL: 嵌套合并和转换

Question

版本是 SQL Server 2012 with SQL Server Management Studio

我的作业要求我创建一个包含 PeopleID、HireDate 和 TermDate 列的 table。 TermDate 将重命名为 Current 并将 Null 值合并为 'Current Employee'。这里的问题是 TermDate 是一个 Null 列，需要转换为文本列才能合并...

我试过很多调整，但我似乎无法弄清楚。这是我当前的迭代。现在我收到错误

Msg 102, Level 15, State 1, Line 5
Incorrect syntax near 'TermDate'.

代码：

select 
   PeopleID
   ,HireDate
   ,coalesce(convert(varchar(10), TermDate, 1) TermDate, 'Current Employee') as [Current]
from 
   WORKERS

感谢帮助

Answer 1

为什么表达式中有两次 TermDate？你只需要它一次作为 convert():

的参数

select PeopleID, HireDate,
       coalesce(convert(varchar(10),TermDate, 1), 'Current Employee') as [Current]
from WORKERS;

Answer 2

select  PeopleID
        ,HireDate
        ,case 
            when TermDate is NULL then 'Current Employee')
            else convert(varchar(10), TermDate, 1)
         end as [Current]
    from WORKERS

SQL: 嵌套合并和转换

SQL: Nesting coalesce and convert

sql

sql-server

coalesce

sql-server-2012