如何从一组列中选择非 NULL 值? [英] How to pick the non-NULL value from a set of columns?

问题描述

我的表格有 1 + 5 列，如下所示.

I have table with 1 + 5 columns as follows.

MemberID ==> 代表 Member_ID

MemberID ==> represents Member_ID

Value1 ==> 代表 Value1

Value1 ==> Represents Value1

Value2 ==> 代表 Value2

Value2 ==> Represents Value2

Value3 ==> 代表 Value3

Value3 ==> Represents Value3

Value4 ==> 代表 Value4

Value4 ==> Represents Value4

Value5 ==> 代表 Value5

Value5 ==> Represents Value5

在任何给定时间只有一列不为空(在 Value1、Value2、Value3、Value4 和 Value5 的集合中).

Only one column is not null at any given time(In the set of Value1, Value2, Value3, Value4 and Value5).

我想运行一个查询，在其中我得到的结果为 Member_ID，Value，其中值是来自 5 个值列中任何一个的非空值.

I want to run a query where in I get the result as Member_ID, Value where the value is non null value from any of the 5 Value columns.

如何在 TSQL 中做到这一点?谢谢，史密斯

How to do that in TSQL? Thank you, Smith

推荐答案

select memberID, coalesce(value1, value2, value3, value4, value5)
from myTable

如果存在所有值都可能为空的可能性，您可能希望默认为一个值.

If the possibility exists that all of the values could be null, you may want to default to a value.

select memberID, coalesce(value1, value2, value3, value4, value5, <default>)
from myTable

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