在CASE WHEN中满足特定条件时删除列 [英] Remove a column when meet a certain condition in CASE WHEN

问题描述

我有以下SQL语句，我想在满足条件时删除某个列。以下是我的SQL语句：

Hi, I have the following SQL statement in which I want to remove a certain column when a condition is met. Below are my SQL statement:

CASE @p_ReportType WHEN 1 THEN NULL WHEN ISNULL(@p_ReportType, 0) THEN row_number() OVER (ORDER BY  EventId desc)+1 END AS MeasurementGroupId 

对于上面的场景，当@p_ReportType为1时，除去MeasurementGroupId，否则保留MeasurementGroupId。任何帮助都表示赞赏。

For the above scenario, when the @p_ReportType is 1 then the MeasurementGroupId is removed else the MeasurementGroupId is remained. Any helps are appreciated.

推荐答案

上面的代码不会删除任何列！它评估条件列表并返回多个可能的结果表达式之一。



请参阅：

CASE（sql） [ ^ ]

Above code does not remove any column! It "evaluates a list of conditions and returns one of multiple possible result expressions".

See:
CASE (sql)[^]

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