CREATE function [dbo].[Fn_Indian_Money_Format]  
(        
@amount MONEY        
)        
RETURNS VARCHAR(50)        
AS        
BEGIN        
     DECLARE @charMoney VARCHAR(50), @RemainingChar VARCHAR(50), @QuoteChar VARCHAR(50)        
     DECLARE @LenStr INT, @val INT, @index INT        
     SELECT @charMoney = CONVERT(VARCHAR(50),@amount)        
     SELECT @QuoteChar = SUBSTRING(@charMoney,1,CHARINDEX('.',@charMoney)-1)        
     SELECT @val = LEN(@charMoney) - LEN(@QuoteChar)        
     SELECT @RemainingChar = SUBSTRING(@charMoney,CHARINDEX('.',@charMoney),@val)        
     SELECT @LenStr = LEN(@QuoteChar)         
     SET @index = 3        
     WHILE (@LenStr > @index)        
     BEGIN        
         SET @QuoteChar = (SELECT STUFF(@QuoteChar, (@LenStr-@index) + 1, 0, ','))        
         SET @index = @index + 2        
     END            
     RETURN isnull(left(@QuoteChar + @RemainingChar, len(@QuoteChar) + len(@RemainingChar)-3),0)
END 

select dbo.fn_Format_Money_Indian (1000) -- Result is 1,000
select dbo.fn_Format_Money_Indian (10000) -- Result is 10,000
select dbo.fn_Format_Money_Indian (100000) -- Result is 1,00,000
select dbo.fn_Format_Money_Indian (1000000) -- Result is 10,00,000

select dbo.fn_Format_Money_Indian (-10000) -- Result is -,10,000 But Reqired Format is -10,000
select dbo.fn_Format_Money_Indian (-1000000) -- Result is -,10,00,000 But Reqired Format is -10,00,000
select dbo.fn_Format_Money_Indian (-100000000) -- Result is -,10,00,00,000 But Reqired Format is -10,00,00,000

CREATE function [dbo].[Fn_Indian_Money_Format]  
(        
@amount MONEY        
)        
RETURNS VARCHAR(50)        
AS        
BEGIN        
     DECLARE @charMoney VARCHAR(50), @RemainingChar VARCHAR(50), @QuoteChar VARCHAR(50)        
     DECLARE @LenStr INT, @val INT, @index INT 	 
     
     Set @charMoney = CONVERT(VARCHAR(50),ABS(@amount))        
     Set @QuoteChar = SUBSTRING(@charMoney,1,CHARINDEX('.',@charMoney)-1)        
     Set @val = LEN(@charMoney) - LEN(@QuoteChar)        
     Set @RemainingChar = SUBSTRING(@charMoney,CHARINDEX('.',@charMoney),@val)        
     Set @LenStr = LEN(@QuoteChar)  
	 
	         
     SET @index = 3        
     WHILE (@LenStr > @index)        
     BEGIN        
         SET @QuoteChar = (SELECT STUFF(@QuoteChar, (@LenStr-@index) + 1, 0, ','))        
         SET @index = @index + 2        
     END
	             
     RETURN CASE SIGN(@amount) When -1 then '-' END+ isnull(left(@QuoteChar + @RemainingChar, len(@QuoteChar) + len(@RemainingChar)-3),0)
END 

DECLARE @amount MONEY
SET @amount = -3211987654321.10 -- [-3,210,987,654,321.10] 

---------------------------------------------------------------------------------------
SELECT
	FormattedAmount = CASE SIGN(@amount) WHEN -1 THEN '-' ELSE '' END + 
		CASE 
		WHEN vl < 4  THEN AmountAsString
		WHEN vl < 6  THEN STUFF(AmountAsString,vl-2,0,',') 
		WHEN vl < 8  THEN STUFF(STUFF(AmountAsString,vl-2,0,','),vl-4,0,',')
		WHEN vl < 10 THEN STUFF(STUFF(STUFF(AmountAsString,vl-2,0,','),vl-4,0,','),vl-6,0,',')
		WHEN vl < 12 THEN STUFF(STUFF(STUFF(STUFF(AmountAsString,vl-2,0,','),vl-4,0,','),vl-6,0,','),vl-8,0,',')
		WHEN vl < 14 THEN STUFF(STUFF(STUFF(STUFF(STUFF(AmountAsString,vl-2,0,','),vl-4,0,','),vl-6,0,','),vl-8,0,','),vl-10,0,',')
		ELSE NULL END
FROM (SELECT 
	vl = CAST(1+LOG10(ABS(@amount)) AS INT), 
	AmountAsString = CONVERT(VARCHAR(50),ABS(@amount))
) d  

---------------------------------------------------------------------------------------
SELECT FormattedAmount = CASE SIGN(@amount) WHEN -1 THEN '-' ELSE '' END + 
	COALESCE(x5.StrAmount, x4.StrAmount, x3.StrAmount, x2.StrAmount, x1.StrAmount, d.StrAmount) 
FROM (SELECT 
	vl = CAST(1+LOG10(ABS(@amount)) AS INT), 
	StrAmount = CONVERT(VARCHAR(50),ABS(@amount))
) d 
CROSS APPLY (SELECT StrAmount = CASE WHEN d.vl > 3  THEN STUFF( d.StrAmount,vl- 2,0,',') END) x1
CROSS APPLY (SELECT StrAmount = CASE WHEN d.vl > 5  THEN STUFF(x1.StrAmount,vl- 4,0,',') END) x2
CROSS APPLY (SELECT StrAmount = CASE WHEN d.vl > 7  THEN STUFF(x2.StrAmount,vl- 6,0,',') END) x3
CROSS APPLY (SELECT StrAmount = CASE WHEN d.vl > 9  THEN STUFF(x3.StrAmount,vl- 8,0,',') END) x4
CROSS APPLY (SELECT StrAmount = CASE WHEN d.vl > 11 THEN STUFF(x4.StrAmount,vl-10,0,',') END) x5

---------------------------------------------------------------------------------------