SQL error when trying to loop in databases and create function - sql-server

Question

I have created a SQL script to loop throw databases and create a function (the aim of the function is to convert RTF to Plain Text).
I put the script of the function creation on a variable and try to execute it using the exec command.
I have used While loop and I have put the request on a varchar variable, then, exec #command
but I get this error:
enter image description here
declare #Total as int
select #Total = count(*) from Temp1
declare #counter as int
set #counter = 1
declare #CurrentVal as varchar(max)
declare #command varchar(max)
while (#counter <= #Total)
begin
select #CurrentVal = name from Temp1 where RowId = #counter
set #command=' use '+#CurrentVal+'
GO
CREATE FUNCTION dbo.fnParseTEXTRTF
(
#rtf VARCHAR(max)
)
RETURNS VARCHAR(max)
AS
BEGIN
DECLARE #Stage TABLE
(
Chr CHAR(1),
Pos INT
)
INSERT #Stage
(
Chr,
Pos
)
SELECT SUBSTRING(#rtf, Number, 1),
Number
FROM master..spt_values
WHERE Type = ''p''
AND SUBSTRING(#rtf, Number, 1) IN (''{'', ''}'')
DECLARE #Pos1 INT,
#Pos2 INT
SELECT #Pos1 = MIN(Pos),
#Pos2 = MAX(Pos)
FROM #Stage
DELETE
FROM #Stage
WHERE Pos IN (#Pos1, #Pos2)
WHILE 1 = 1
BEGIN
SELECT TOP 1 #Pos1 = s1.Pos, #Pos2 = s2.Pos
FROM #Stage AS s1
INNER JOIN #Stage AS s2 ON s2.Pos > s1.Pos
WHERE s1.Chr = ''{''
AND s2.Chr = ''}''
ORDER BY s2.Pos - s1.Pos
IF ##ROWCOUNT = 0
BREAK
DELETE
FROM #Stage
WHERE Pos IN (#Pos1, #Pos2)
UPDATE #Stage
SET Pos = Pos - #Pos2 + #Pos1 - 1
WHERE Pos > #Pos2
SET #rtf = STUFF(#rtf, #Pos1, #Pos2 - #Pos1 + 1, '''')
END
SET #Pos1 = PATINDEX(''%\cf[0123456789][0123456789 ]%'', #rtf)
WHILE #Pos1 > 0
SELECT #Pos2 = CHARINDEX('' '', #rtf, #Pos1 + 1), #rtf = STUFF(#rtf, #Pos1, #Pos2 - #Pos1 + 1, ''''), #Pos1 = PATINDEX(''%\cf[0123456789][0123456789 ]%'', #rtf)
SELECT #rtf = REPLACE(#rtf, ''\pard'', ''''), #rtf = REPLACE(#rtf, ''\par'', ''''), #rtf = case when LEN(#rtf)>0 then LEFT(#rtf, LEN(#rtf) - 1) else #rtf end
SELECT #rtf = REPLACE(#rtf, ''\b0 '', ''''), #rtf = REPLACE(#rtf, ''\b '', '''')
SELECT #rtf = STUFF(#rtf, 1, CHARINDEX('' '', #rtf), '''')
RETURN #rtf
end'
set #counter = #counter + 1
exec #command
end

Answer 1

As i understand, the function is correct, the main problem to execute statement for function creation across multiple databases.
GO can't be used here, it's not sql, it's instruction to client to execute all statements in scope
Unfortunately, you can't create function not in current database, using [DatabaseName].[schema].[FuncName].
I can propose such technique to solve the problem, code just for example
declare #funccode nvarchar(4000);
set #funccode='CREATE FUNCTION [dbo].[fntest]
(
)
RETURNS int
AS
BEGIN
RETURN 1
END;'
declare #dbname nvarchar(100)='TestDatabase'
declare #statement nvarchar(max) ='use '+#dbname+';
exec (#func);'
exec sp_executesql #stmt = #statement,#params=N'#func nvarchar(4000)',#func=#funccode;
Th idea - to switch current database inside exec statement and call new exec statement, when current database is already set