如果第一列在sql中为null，如何将变量与secnd列进行比较？ [英] how to compare a variable with secnd column if first column is null in sql?

问题描述

如果第一列为空，如何将where条件中的变量与第二列进行比较？



我的sql查询如下所示

How to compare a variable in where condition to second column if first column is null ?

my sql query is like below

select * from table where column1 = @variable

现在我想要的是如果column1的值为null，那么它应该检查第二列。如果column1的值不为null，则应仅与该列进行比较。

now i want is if the value of column1 is null then it should check with column two. if the value of column1 is not null it should compare with that column only.

select * from table where column2 = @variable

推荐答案

select * from table where column1 = @variable OR (column1 IS NULL AND column2 = @variable)

select * from table
where
 @variable = IsNull([Column1], [Column2])

试试这样：

Try like this :

select * from table 
where 
Case WHEN column1 is not null 
THEN
column1 
 ELSE
 column2 END = @variable

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