Conversion failed when converting the varchar value ' and f.FUNCTION_ID= CAST(' to data type int - sql

Question

I am trying to make the procedure where I can get the data from MS SQL. Here I am getting the error
Msg 245, Level 16, State 1, Procedure GET_FUNCTIONS, Line 15 [Batch Start Line 33]
Conversion failed when converting the varchar value ' and f.FUNCTION_ID in '' to data type int.
CREATE procedure [dbo].[GET_FUNCTIONS]
#Function_Id int,
#EntityId int,
#OrderBy varchar(10)
as
begin
declare #Sql nvarchar(max)
if(#Function_Id=0 AND #EntityId=0)
set #Sql = 'select
f.Function_Code,f.FUNCTION_ID,f.EntityId,be.ENTITY_SHORT_NAME,f.FUNCTION_NAME,
f.FUNCTION_DESC,f.CREATED_DATE,f.MODIFIED_DATE from FUNCTIONS f
inner join BusinessEntity be on f.EntityId=be.ID
WHERE f.ACTIVE=1 '
if(#Function_Id!=0)
set #Sql += ' and f.FUNCTION_ID in ''' + #Function_Id + ''''
if(#EntityId!=0)
set #Sql += ' and f.EntityId = cast('+convert(varchar(12) ,#EntityId)+') '
set #Sql += ' order by FUNCTION_ID '+ #OrderBy
print #Sql
end
GO

Answer 1

Thanks everyone for your answers. I have got the answer by my own.
I have removed if(#Function_Id=0 AND #EntityId=0) and changed the data type of #Function_Id and #EntityId to varchar(100), so solved all errors.

Answer 2

I'm, making a few guesses here, which I add some comments about, however, this should be what you are after. I firstly ensure that I parametrise the values, but also validate and quote the value of #OrderBy:
CREATE PROCEDURE [dbo].[GET_FUNCTIONS] #Function_Id int =NULL, --Instead of passing 0as "select all" use NULL
#EntityId int = NULL, --Instead of passing 0as "select all" use NULL
#OrderBy nvarchar(4) --guessing this is mean to be ASC or DESC?
AS
BEGIN
IF #OrderBy NOT IN (N'ASC','DESC')
--Error is not ASC or DESC
THROW 51473, N'#OrderBy can only have a value of ''ASC'' or ''DESC''.',16; --51473 was a random error number; you can use one that is appropriate for your environment.
DECLARE #SQL nvarchar(MAX),
#CRLF nchar(2) = NCHAR(13) + NCHAR(10);
SET #SQL = N'SELECT f.Function_Code,' + + #CRLF +
N' f.FUNCTION_ID,' + + #CRLF +
N' f.EntityId,' + + #CRLF +
N' be.ENTITY_SHORT_NAME,' + + #CRLF +
N' f.FUNCTION_NAME,' + + #CRLF +
N' f.FUNCTION_DESC,' + + #CRLF +
N' f.CREATED_DATE,' + + #CRLF +
N' f.MODIFIED_DATE' + + #CRLF +
N'FROM FUNCTIONS f' + + #CRLF +
N' INNER JOIN BusinessEntity be ON f.EntityId = be.ID' + + #CRLF +
N'WHERE f.ACTIVE = 1';
IF (#Function_Id IS NOT NULL)
SET #SQL = #SQL + #CRLF + N' AND f.FUNCTION_ID = #Function_Id'
IF (#EntityId IS NOT NULL)
SET #SQL = #SQL + #CRLF + N' AND f.EntityId = #EntityId'
SET #SQL = #SQL + #CRLF +
N'ORDER BY F.FUNCTION_ID ' + QUOTENAME(#OrderBy) + N';'
--PRINT #SQL; --Uncomment for debugging.
EXEC sp_executesql #SQL, N'#Function_Id int, #EntityId int', #Function_Id, #EntityId;
END;
GO