sql - 在 SQL Server 2008 中使用 CASE 更新多列

Question

我有以下 SQL 语句：

 update data 
  set [sub_st_pc]= 
    case 
          when [R 6] is not null  then [R 6] 
      when [R 5] is not null  then [R 5]
      when [R 4] is not null  then [R 4]
      when [R 3] is not null  then [R 3]
      when [R 2] is not null  then [R 2]
      else sub_st_pc
    end

但我需要根据每个时间更新另一列，如下所示：

 when [R 6] is not null  then [R 6], [temp] = 6
 when [R 5] is not null  then [R 5], [temp] = 5

我知道这是错误的。

有任何想法吗？

Answer 1

您可以使用COALESCE来更轻松地设置第一列。你需要一个单独的 CASE 语句来设置[temp]，而 COALESCE 不会帮助你。

update data 
set [sub_st_pc]= COALESCE([R 6], [R 5], [R 4], [R 3], [R 2], [sub_st_pc]),
    [temp] = case 
               when [R 6] is not null  then 6 
               when [R 5] is not null  then 5
               when [R 4] is not null  then 4
               when [R 3] is not null  then 3
               when [R 2] is not null  then 2
               else NULL
             end

Answer 2

update data 
  set [col1]= case when [R1] is not null  then [R1] else [col1] end,
      [col2]= case when [R2] is not null  then [R2] else [col2] end,
       .....

Answer 3

你的问题不清楚。只需编写类似于您为一列编写的更新语句，但对于许多列，例如

update Data
set Col1 = case when Col2 is not null then col2 else Col1 end,
Col2 = case when Col3 is not null then Col3 else Col2 end