將varchar轉換為int時轉換失敗

Question

我在SQL中遇到轉換錯誤。 我已經嘗試將Cast和Convert轉換為int，但是失敗了。

SELECT 
    ProdId, ParentCat, ProdFullName, ProdImage 
FROM 
    Product
WHERE
    ProdId IN (SELECT Compared FROM Product WHERE ProdId = 10803)

• ProdId為int
• Compared列是varchar

Compared列值是：

32879, 10844, 10747, 81113, 8001, 81469

Answer 1

SELECT 
    ProdId, ParentCat, ProdFullName, ProdImage 
FROM 
    Product
WHERE
    ProdId IN (SELECT convert(int,ltrim(rtrim(Compared))) 
              FROM Product WHERE ProdId = 10803)

進一步了解CAST和CONVERT

Answer 2

在這種情況下，您只需將ProdId轉換為varchar。

WHERE
CAST(ProdId AS varchar(10)) IN (SELECT Compared FROM Product WHERE ProdId = 10803)

Answer 3

在這種情況下，您應該將查詢構建為字符串並執行它DECLARE @query VARCHAR(MAX) SELECT @query = 'SELECT ProdId, ParentCat, ProdFullName, ProdImage FROM Product WHERE ProdId IN (' + Compared + ')' FROM Product WHERE ProdId = 10803 EXEC (@query)