RAISERROR中的连接消息

Question

这里的正确语法是什么？

If (@timestamp < (Select PromoStartTimestamp From @promo)) 
    RAISERROR('Code not valid until ' + (Select PromoStartTimestamp From @promo) 
       ,16 
       ,1); 

我已经试过：

If (@timestamp < (Select PromoStartTimestamp From @promo)) 
    RAISERROR(N'Code not valid until @starttimestamp' 
       ,16 
       ,1 
       ,(Select PromoStartTimestamp From @promo)); 

迈克尔·弗雷德里克森的回答给我的Incorrect syntax near 'CAST'.

Answer 1

错误可以在RAISERROR使用%s作为一个字符串替换参数：

DECLARE @PromoStartTimestamp DATETIME 
DECLARE @PromoStartTimestampString VARCHAR(50) 

SELECT @PromoStartTimestamp = PromoStartTimestamp From @promo 
SELECT @PromoStartTimestampString = CAST(@PromoStartTimestamp AS VARCHAR) 

If (@timestamp < @PromoStartTimestamp) 
    RAISERROR(N'Code not valid until %s' 
       ,16 
       ,1 
       ,@PromoStartTimestampString);