当 CAST 作为 NVarChar 时删除尾随 0

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 ie 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, ie

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

--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

Answer 4

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 5

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