SQL：使用大小写何时更改列值

I am creating new columns but in particular I want to say if a value of a column is equal to a value, then change a corresponding column. For example:

我正在创建新列，但特别是我想说如果列的值等于某个值，则更改相应的列。例如：

SELECT
     Col1 as c1
    ,Col2 as c2
    ,CASE CAST([COB] as varchar(50))
        WHEN 'Engineering' then set c1 = 1
        ELSE 0
    END AS [Class of Business]
FROM
     ....

but I can't get it to work, for instance if a entry in the column [COB] was 'engineering' then I want it to set (on the same row) the column c1 to 0, else just fill the column c1 with 0's

但我不能让它工作，例如，如果[COB]列中的条目是'工程'，那么我希望它将列c1设置（在同一行上）为0，否则只需填写列c1 0的

4 个解决方案

#1

If you only want to query your table, you can return 1 or 0 in base of COB status without reassign to c1 the new value.

如果您只想查询表，则可以在COB状态的基础上返回1或0，而无需将新值重新分配给c1。

Try this:

尝试这个：

SELECT
CASE 
    WHEN CAST([COB] as varchar(50)) = 'Engineering' then 1
    ELSE Col1
END AS c1,
Col2 as c2
FROM ...

#2

So when COB = Engineering you want c1 to be 1 otherwise just the current value of C1. If that is the cae then......

因此，当COB =工程时，您希望c1为1，否则只是C1的当前值。如果那是cae那么......

SELECT
    CASE CAST([COB] as varchar(50))
        WHEN 'Engineering' then 1
        ELSE c1
    END AS c1
    ,Col2 as c2
FROM
..

#3

That's not the way SELECT works. You're looking for something like this:

那不是SELECT的工作方式。你正在寻找这样的东西：

SELECT
    --Col1 as c1
    CASE CAST([COB] as varchar(50))
        WHEN 'Engineering' then 1
        ELSE 0
    END AS c1 
    ,Col2 as c2
    ,COB as [Class of Business]
FROM

#4

Why are you doing the cast()?

你为什么要做演员（）？

SELECT Col1 as c1,
       Col2 as c2,
       (CASE WHEN [COB] = 'Engineering' THEN 1 ELSE 0 END) as [Class of Business]
FROM . . .;

You can use a searched CASE for this purpose. But with one comparison, I think the above is easier to read.

您可以使用搜索的CASE来实现此目的。但通过一次比较，我认为上述内容更容易阅读。

#1