Remove trailing 0 when CAST as NVarChar - sql

Question

I have data as Decimal(15,4) and values can be like 14.0100, or 14.0000, or 14.9999
For integration with other system we have to store this kind of data in NVarChar(MAX) attributes table. When I run CAST(Field AS NVarChar(MAX)) I get string values like 0.0000
What I want is to trim trailing zeros (and period if needed) from those strings because data later used in online transmission and it's much better to send 14 instead of 14.0000
How do I do that?

Answer 1

SQL Server 2012+ you could use FORMAT, with SQL Server 2008 you could use string manipulation:
CREATE TABLE #tab(col DECIMAL(15,4));
INSERT INTO #tab(col)
VALUES (14.0100), (14.0000),
(14.9999), (10), (0),
(-1), (-10), (-12.01), (-12.10);
SELECT
col
,result_2012 = FORMAT(col, '########.####')
,result_2008 = CASE
WHEN col = 0 THEN '0'
ELSE LEFT(col,LEN(col) -
CASE WHEN PATINDEX('%[1-9]%', REVERSE(col)) < PATINDEX('%[.]%', REVERSE(col))
THEN PATINDEX('%[1-9]%', REVERSE(col)) - 1
ELSE PATINDEX('%[.]%', REVERSE(col))
END)
END
FROM #tab;
LiveDemo

Answer 2

You could try casting the Decimal numbers to floats before casting then casting them to NVarChars i.e. CAST(CAST(Field as Float(8)) as NVarChar(MAX)). The only issue you might have with this is if any of your existing numbers have a greater precision than an 8 byte float can deal with which should be easy enough to check for.
It would also be possible to remove the extra zeros after you've casted the numbers as strings using case statements, i.e.
case when right(Field, 4) = '0000' then
left(Field, len(Field) - 5) -- -5 to remove the decimal point
else case when right(Field, 3) = '000' Then
left(Field, len(Field) - 3)
else case when right(Field, 2) = '00' Then
left(Field, len(Field) - 2)
else case when right(Field, 1) = '0' Then
left(Field, len(Field) - 1)
end end end end

Answer 3

simple casting to REAL then back to varch(max) if you want will remove the leading 0s as follows:
declare #a as Decimal(15,4)=14.0010
select cast(cast (#a as real) as varchar(max)) as a2
-- ouptut is 14.001
declare #a as Decimal(15,4)=14.0000
select cast(cast (#a as real) as varchar(max)) as a2
-- output is 14

Answer 4

The Idea here is to use the built in string function of Trimming spaces to TRIM ZEROs from the converted decimal as follows:
declare #d as Decimal(15,4)=11400012.00000, #s0 VARCHAR(MAX), #s VARCHAR(MAX)
set #s0=cast(#d as varchar(max))
set #s=left(#s0,len(rtrim(replace(#s0,'0',' '))))
if right(#s,1)='.' set #s=left(#s,len(#s)-1)
select #s
-- returns 11400012.001
You also can define the function to do this task for you:
CREATE FUNCTION TRIM0(#s0 varchar(max))
RETURNS varchar(max)
AS
BEGIN
declare #s varchar(max)=''
set #s=left(#s0,len(rtrim(replace(#s0,'0',' '))))
if right(#s,1)='.' set #s=left(#s,len(#s)-1)
return #s
END

Answer 5

--With a lot of fantasy
--Tip: to optimize performances, first select values in a #-table, then do this transformation.
select
left( cast(Field as varchar(max)), charindex('.', cast(Field as varchar(max))) - 1) +
Case when reverse(cast(cast(reverse(substring(cast(Field as varchar), charindex('.', cast(Field as varchar)) + 1 ,4)) as int) as nvarchar)) = 0 Then '' Else
'.' + reverse(cast(cast(reverse(substring(cast(Field as varchar), charindex('.', cast(Field as varchar)) + 1 ,4)) as int) as nvarchar)) End