SQL服務器：算術溢出錯誤將表達式轉換爲數據類型BIGINT

Question

這裏是我的查詢的序列：

SELECT 
     CASE 
     WHEN ((BarCode IS NOT NULL) AND (ExternelBarCode IS NULL)) THEN BarCode 
     WHEN ((BarCode IS NULL) AND (ExternelBarCode IS NOT NULL)) THEN CAST(ExternelBarCode AS bigint) 
     ELSE ExternelBarCode -- When both exist 
     END AS TicketBarCode 
... 

當我運行它，我有以下消息：

算術溢出將表達式轉換爲數據類型bigint時出錯。

列BarCode是bigint類型，並且列ExternelBarCode是varchar(250)類型。

BarCode = 178625624324, 
ExternelBarCode = 2015591149641227565492 

我該如何解決這個問題？

Answer 1

2,015,591,149,641,227,565,492的值大於bigint 2^63-1（9,223,372,036,854,775,807）中允許的最大值，因此轉換是不可能的。

如果需要返回一個數值，您可以將其轉換爲decimal(38,0)

SELECT 
     CASE 
     WHEN ((BarCode IS NOT NULL) AND (ExternelBarCode IS NULL)) THEN CAST(BarCode as decimal(38,0)) 
     WHEN ((BarCode IS NULL) AND (ExternelBarCode IS NOT NULL)) THEN CAST(ExternelBarCode AS decimal(38,0)) 
     ELSE cast(ExternelBarCode as decimal(38,0)) -- When both exist 
     END AS TicketBarCode