SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:      Insus.NET
-- Create date: 2019-05-13
-- Update date: 2019-05-13
-- Description: 保留一个空格
-- =============================================
CREATE FUNCTION [dbo].[svf_Leave_A_Space] 
( 
    @InputString NVARCHAR(MAX)
) 
RETURNS NVARCHAR(MAX)
AS
BEGIN
    DECLARE @Index INT = 1
    DECLARE @CurrentChar CHAR(1)
    DECLARE @PreviousChar CHAR(1)
    DECLARE @Str NVARCHAR(MAX) = N''
 
    WHILE @Index <= LEN(@InputString)
    BEGIN
        SET @CurrentChar = SUBSTRING(@InputString, @Index, 1)
        SET @PreviousChar = SUBSTRING(@InputString, @Index - 1, 1)
        IF @CurrentChar != ' ' OR @CurrentChar != @PreviousChar                
            SET @Str = @Str + CAST(@CurrentChar AS NVARCHAR(MAX))
        SET @Index = @Index + 1
    END
    RETURN @Str
END
GO