Sql server 如果结果存在，则执行存储过程

我想在现有存储过程中获得一些帮助，我想从中获得一个输出，其中我有表

[DVMT30\u EVENT\u PROCESSOR].[StateMachine].[Snapshots]

中的匹配记录，其中

CrossbarRouter=@CrossbarRouter

是存储过程的一部分

仅当

@OUT

结果集与

@Crossbar

参数匹配时，我才希望执行存储过程

[StateMachine].[UpdateSnapshots]

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

DECLARE @OUT NVARCHAR(100); 

CREATE PROCEDURE [StateMachine].[UpdateSnapshots] 
    @SystemName [NVARCHAR](128), 
    @IntrestingEvents VARCHAR(128), 
    @StateMachine_JSON [NVARCHAR](MAX),
    @StateMachine_Object [NVARCHAR](MAX),
    @CrossbarRouter VARCHAR(128)
AS
    SET @OUT = (SELECT [CrossbarRouter] 
                FROM [DVMT30_EVENT_PROCESSOR].[StateMachine].[Snapshots] 
                WHERE CrossbarRouter = @CrossbarRouter)

    IF EXISTS (SELECT * FROM [DVMT30_EVENT_PROCESSOR].[StateMachine].[Snapshots] 
               WHERE SystemName = @SystemName)
        UPDATE [DVMT30_EVENT_PROCESSOR].[StateMachine].[Snapshots]
        SET IntrestingEvents = @IntrestingEvents, 
            StateMachine_JSON = @StateMachine_JSON, 
            StateMachine_Object = @StateMachine_Object, 
            CrossbarRouter = @CrossbarRouter
        WHERE SystemName = @SystemName;
    ELSE
        INSERT INTO [DVMT30_EVENT_PROCESSOR].[StateMachine].[Snapshots] (SystemName, IntrestingEvents, StateMachine_JSON, StateMachine_Object, CrossbarRouter)
        VALUES (@SystemName, @IntrestingEvents, @StateMachine_JSON, @StateMachine_Object, @CrossbarRouter);
GO

---

如果没有匹配项，您可以返回：

SELECT @OUT = [CrossbarRouter] 
    FROM [DVMT30_EVENT_PROCESSOR].[StateMachine].[Snapshots] 
    WHERE CrossbarRouter = @CrossbarRouter

IF @OUT IS NULL 
    RETURN 0;