字母转为大写字母

 自定义Scalar-valued Function函数，把字母转换为大写字母。

字母转为大写字母a-->A;b-->B;c-->C;...z-->Z
如果非字母转换为\'\'

 

 

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

-- =============================================
-- Author:      Insus.NET
-- Blog:        https://insus.cnblogs.com
-- Create date: 2019-05-31
-- Update date: 2019-05-31
-- Description: 字母转为大写字母a-->A;b-->B;c-->C;...z-->Z
--              如果非字母转换为\'\'
-- =============================================
CREATE FUNCTION [dbo].[svf_ConvertLettertoUppercaseLetter] 
(
  @Letter CHAR(1)
) RETURNS CHAR(1)
AS
BEGIN
    DECLARE @UppercaseLetter CHAR(1) = \'\'          
    IF LEN(ISNULL(@Letter,\'\')) > 0 
    BEGIN
        IF ASCII(@Letter) % 97 + 1 <= 26
            SET @UppercaseLetter = CHAR(ASCII(@Letter) - (97 - 65)) 

        IF ASCII(@Letter) % 65 + 1 <= 26
            SET @UppercaseLetter = @Letter
    END      
    RETURN @UppercaseLetter
END
GO

Source Code

 

例子演示：

 

SELECT
[dbo].[svf_ConvertLettertoUppercaseLetter] (\'A\') AS \'A\',
[dbo].[svf_ConvertLettertoUppercaseLetter] (\'a\') AS \'a\',
[dbo].[svf_ConvertLettertoUppercaseLetter] (\'B\') AS \'B\',
[dbo].[svf_ConvertLettertoUppercaseLetter] (\'b\') AS \'b\',
[dbo].[svf_ConvertLettertoUppercaseLetter] (\'C\') AS \'C\',
[dbo].[svf_ConvertLettertoUppercaseLetter] (\'c\') AS \'c\',
[dbo].[svf_ConvertLettertoUppercaseLetter] (\'Z\') AS \'Z\',
[dbo].[svf_ConvertLettertoUppercaseLetter] (\'z\') AS \'z\',
[dbo].[svf_ConvertLettertoUppercaseLetter] (\'$\') AS \'$\'

Source Code

 

以上函数，只能对单独字母进行转换，如果一次性转换一串字符呢，这个功能可以有，参考下面：

 

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:      Insus.NET
-- Blog:        https://insus.cnblogs.com
-- Create date: 2019-05-31
-- Update date: 2019-05-31
-- Description: 小写字符转为大写字母
-- =============================================
CREATE FUNCTION [dbo].[svf_ConvertToUppercase] 
(
    @Letter NVARCHAR(MAX)
) 
RETURNS NVARCHAR(MAX)
AS
BEGIN
    DECLARE @Uppercase NVARCHAR(MAX) = N\'\',@i INT = 1    
    WHILE @i <= LEN(@Letter) 
        BEGIN          
            DECLARE @currentChar CHAR(1) = SUBSTRING(@Letter, @i, 1)
            SET @Uppercase = @Uppercase + 
            CASE WHEN ASCII(@currentChar) % 97 + 1 <= 26 
            THEN CHAR(ASCII(@currentChar) - (97 - 65)) 
            ELSE
               @currentChar
            END 
   
            SET @I = @I + 1 
        END
        
    RETURN @Uppercase
END
GO

Source Code

 

示例：