基于否定更新一列的查询 [英] Update query on one column based on negative

问题描述

需要根据A列更新B列，

条件 - 如果A列（数据类型 - Float）为负，则将-1放入B列，反之亦然。 />


使用SQL Server 2014



我尝试过：



如果更新查询但未能从A列中提取否定的情况



来自解决方案的OP代码：

Need to Update a column B on basis on Column A,
Condition - If Column A(data type-Float) is Negative then Put -1 Sign in Column B and vice versa.

using SQL Server 2014

What I have tried:

Case if update query but failed to extract negative from column A

OP Code from solution:

update v_table1 set ColumnB= case when ColumnA <0 then -1 when ColumnA >0 then 1 when ColumnA =0 then 0 else null end

推荐答案

很难从

Quote：

条件 - 如果列A（数据类型 - 浮点数）为负，则输入-1登录列B，反之亦然

Condition - If Column A(data type-Float) is Negative then Put -1 Sign in Column B and vice versa

您已经拥有的代码是放置ColumnB中的值似乎有效，但你已经提到了符号。



所以如果ColumnB是char类型那么您似乎想要

The code you already have is putting a value in ColumnB and appears to work, but you have referred to a "sign".

So if ColumnB is a char type then you appear to want

update v_table1 set ColumnB= case when Isnull(ColumnA,0) <0 then '-' when Isnull(ColumnA,0) >0 then '1' else '0' end

注意我拿出了你的null。



但是，如果你真正想要的是根据ColumnA的值否定ColumnB，那么你想要这样的东西

Note I took out your null.

But, if what you really want is to negate ColumnB based on the value of ColumnA then you want something like this

update v_table1 set ColumnB= case when Isnull(ColumnA,0) <0 then -1 * ColumnB when Isnull(ColumnA,0) >0 then ColumnB else 0 end

请注意，这仅在ColumnB尚未为负数时才有效。



如果这不是您要求的那么请使用有问题或评论吗？此解决方案旁边的链接我将尝试进一步帮助

Note this will only work if ColumnB is not already negative.

If this is not quite what you were asking then use the "Have a Question or Comment?" link next to this solution and I will try to help further

更新v_table1设置ColumnB = ColumnA时的情况< 0然后当ColumnA> 0时为-1然后当ColumnA = 0时为1然后0 else null end

update v_table1 set ColumnB= case when ColumnA <0 then -1 when ColumnA >0 then 1 when ColumnA =0 then 0 else null end

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