字母转为小写字母

传入大写字母，输出为小字母，如果传入小写字母，直接输出小写字母。传入非字母，输出为‘’。

如：A-->a;B-->b;C-->c;...Z-->z

参考函数：

 

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: 字母转为小写字母A-->a;B-->b;C-->c;...Z-->z
--              如果非字母转换为''
-- =============================================
CREATE FUNCTION [dbo].[svf_ConvertLetterToLowercaseLetter] 
(
  @Letter CHAR(1)
) RETURNS CHAR(1)
AS
BEGIN
    DECLARE @LowercaseLetter CHAR(1) = ''          
    IF LEN(ISNULL(@Letter,'')) > 0 
    BEGIN
        IF ASCII(@Letter) % 65 + 1 <= 26
            SET @LowercaseLetter = CHAR(ASCII(@Letter) + (97 - 65)) 
        
        IF ASCII(@Letter) % 97 + 1 <= 26
            SET @LowercaseLetter = @Letter   
    END
    RETURN @LowercaseLetter
END
GO

Source Code