SQL、CONVERT、CAST 数据类型？

Question

我不确定如何在此脚本中使用 CAST 或 CONVERT。
SQL 说：

将 varchar 值 'Amazing' 转换为数据时转换失败 输入整数。

谁能告诉我怎么做？

USE AdventureWorks2012  
GO

DECLARE @Number01 AS INT
DECLARE @Number02 AS INT
DECLARE @Number03 AS INT
DECLARE @Number04 AS INT
DECLARE @Number05 AS INT
DECLARE @Number06 AS INT
DECLARE @Number07 AS INT
DECLARE @Text01 AS VARCHAR (15)


SET @Number01 = 150
SET @Number02 = 200
SET @Number03 = 350
SET @Number04 = 450
SET @Number05 = 550
SET @Number06 = 650
SET @Number07 = 800
SET @Text01 = 'Amazing'


SELECT  A.ProductID  ,A.Name  ,A.ProductModelID  ,A.ProductNumber ,A.MakeFlag  ,A.Color  ,A.SafetyStockLevel
                ,A.StandardCost ,A.ListPrice,A.DaysToManufacture ,A.SellEndDate ,A.ModifiedDate ,A.ListPrice
                ,B.Name ,B.ListPrice ,B.Adjusted_List_Price ,C.ProductDescriptionID ,C.Description
                ,C.ModifiedDate ,D.ProductID ,D.StartDate ,D.EndDate ,D.ListPrice ,D.ModifiedDate, E.Name 
                ,E.CatalogDescription,E.ModifiedDate ,F.ReferenceOrderID ,F.TransactionDate
                ,F.TransactionID ,F.Quantity
                ,IIF(A.ListPrice >=@Number01,CAST((@Number01 *@Number02 + @Number03) AS nvarchar(50)), 100 + @Number01) AS [Test90]
                ,IIF(A.ListPrice >=@Number02,CAST((@Number01 *@Number02 + @Number03) AS nvarchar(50)), 'GG') AS [Test91]
                ,PATINDEX('%M94B%', A.ProductNumber) AS [Test92]
                ,PATINDEX('%M63S%', A.ProductNumber) AS [Test94]
                ,CASE 
                WHEN A.ProductNumber LIKE '%M94B%' THEN PATINDEX('%M94B%', A.ProductNumber) * 2
                WHEN A.ProductNumber LIKE '%M63S%' THEN  5 * @Number01
                WHEN A.ProductNumber LIKE '%T98U%' THEN @Text01
            END AS [Test95]

FROM  [Production].[Product] AS A
INNER JOIN [Production].[Product_2] AS B
ON A.Name = B.Name

INNER JOIN  [Production].[ProductDescription] AS C
ON A.ProductID = C.ProductDescriptionID

INNER JOIN  [Production].[ProductListPriceHistory] AS D
ON A.ProductID = D.ProductID

INNER JOIN   [Production].[ProductModel] AS E
ON A.ProductModelID = E.ProductModelID

FULL JOIN [Production].[TransactionHistory] AS F
ON A.ProductID = F.ProductID

WHERE A.ProductModelID IS NOT NULL
AND A.Color IS NOT NULL AND F.Quantity IS NOT NULL

Answer 1

试试这个

USE AdventureWorks2012  
GO

DECLARE @Number01 AS INT
DECLARE @Number02 AS INT
DECLARE @Number03 AS INT
DECLARE @Number04 AS INT
DECLARE @Number05 AS INT
DECLARE @Number06 AS INT
DECLARE @Number07 AS INT
DECLARE @Text01 AS VARCHAR (15)


SET @Number01 = 150
SET @Number02 = 200
SET @Number03 = 350
SET @Number04 = 450
SET @Number05 = 550
SET @Number06 = 650
SET @Number07 = 800
SET @Text01 = 'Amazing'


SELECT  A.ProductID  ,A.Name  ,A.ProductModelID  ,A.ProductNumber ,A.MakeFlag  ,A.Color  ,A.SafetyStockLevel
                ,A.StandardCost ,A.ListPrice,A.DaysToManufacture ,A.SellEndDate ,A.ModifiedDate ,A.ListPrice
                ,B.Name ,B.ListPrice ,B.Adjusted_List_Price ,C.ProductDescriptionID ,C.Description
                ,C.ModifiedDate ,D.ProductID ,D.StartDate ,D.EndDate ,D.ListPrice ,D.ModifiedDate, E.Name 
                ,E.CatalogDescription,E.ModifiedDate ,F.ReferenceOrderID ,F.TransactionDate
                ,F.TransactionID ,F.Quantity
                ,IIF(A.ListPrice >=@Number01,CAST((@Number01 *@Number02 + @Number03) AS nvarchar(50)), 100 + @Number01) AS [Test90]
                ,IIF(A.ListPrice >=@Number02,CAST((@Number01 *@Number02 + @Number03) AS nvarchar(50)), 'GG') AS [Test91]
                ,PATINDEX('%M94B%', A.ProductNumber) AS [Test92]
                ,PATINDEX('%M63S%', A.ProductNumber) AS [Test94]
                ,CASE 
                WHEN A.ProductNumber LIKE '%M94B%' THEN cast(PATINDEX('%M94B%', A.ProductNumber) * 2  as varchar(100))
                WHEN A.ProductNumber LIKE '%M63S%' THEN cast( 5 * @Number01 as varchar(100))
                WHEN A.ProductNumber LIKE '%T98U%' THEN @Text01
            END AS [Test95]

FROM  [Production].[Product] AS A
INNER JOIN [Production].[Product_2] AS B
ON A.Name = B.Name

INNER JOIN  [Production].[ProductDescription] AS C
ON A.ProductID = C.ProductDescriptionID

INNER JOIN  [Production].[ProductListPriceHistory] AS D
ON A.ProductID = D.ProductID

INNER JOIN   [Production].[ProductModel] AS E
ON A.ProductModelID = E.ProductModelID

FULL JOIN [Production].[TransactionHistory] AS F
ON A.ProductID = F.ProductID

WHERE A.ProductModelID IS NOT NULL
AND A.Color IS NOT NULL AND F.Quantity IS NOT NULL

Answer 2

在您的示例中，CASE 语句假定每个WHEN 子句的返回数据类型为INT，因为第一个WHEN..THEN 返回number。

SQL Server 认为在第三个WHEN..THEN，结果将是INT 和第一个和第二个一样。

您通过在第三个 WHEN..THEN 中返回 varchar 数据类型来打破 SQL Server 的假设，这是不正确的。 Amazing 不能转换为 INT

CASE 语句中的所有路径都应返回相同的数据类型。