Removing leading zeroes from a field in a SQL statement

select substring(ColumnName, patindex('%[^0]%',ColumnName), 10)

If you want the query to return a 0 instead of a string of zeroes or any other value for that matter you can turn this into a case statement like this:

select CASE
      WHEN ColumnName = substring(ColumnName, patindex('%[^0]%',ColumnName), 10) 
       THEN '0'
      ELSE substring(ColumnName, patindex('%[^0]%',ColumnName), 10) 
      END

You can try this - it takes special care to only remove leading zeroes if needed:

DECLARE @LeadingZeros    VARCHAR(10) ='-000987000'

SET @LeadingZeros =
      CASE WHEN PATINDEX('%-0', @LeadingZeros) = 1   THEN 
           @LeadingZeros
      ELSE 
           CAST(CAST(@LeadingZeros AS INT) AS VARCHAR(10)) 
      END   

SELECT @LeadingZeros

Or you can simply call

CAST(CAST(@LeadingZeros AS INT) AS VARCHAR(10)) 

Here is the SQL scalar value function that removes leading zeros from string:

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:      Vikas Patel
-- Create date: 01/31/2019
-- Description: Remove leading zeros from string
-- =============================================
CREATE FUNCTION dbo.funRemoveLeadingZeros 
(
    -- Add the parameters for the function here
    @Input varchar(max)
)
RETURNS varchar(max)
AS
BEGIN
    -- Declare the return variable here
    DECLARE @Result varchar(max)

    -- Add the T-SQL statements to compute the return value here
    SET @Result = @Input

    WHILE LEFT(@Result, 1) = '0'
    BEGIN
        SET @Result = SUBSTRING(@Result, 2, LEN(@Result) - 1)
    END

    -- Return the result of the function
    RETURN @Result

END
GO

In case you want to remove the leading zeros from a string with a unknown size.

You may consider using the STUFF command.

Here is an example of how it would work.

SELECT ISNULL(STUFF(ColumnName
                   ,1
                   ,patindex('%[^0]%',ColumnName)-1
                   ,'')
             ,REPLACE(ColumnName,'0','')
             )

See in fiddler various scenarios it will cover

https://dbfiddle.uk/?rdbms=sqlserver_2012&fiddle=14c2dca84aa28f2a7a1fac59c9412d48

To remove leading 0, You can multiply number column with 1 Eg: Select (ColumnName * 1)

you can try this SELECT REPLACE(columnname,'0','') FROM table