Why do I get this error in SQL Server? How to fix it? - sql

Question

I am creating a stored procedure to insert to a table. Following would provide my table columns are
Create Table Item
(
ID char(20),
Name varchar(max) NOT NULL,
Brand char(10) NOT NULL,
Category char(10) NOT NULL,
Unit_Of_Measure char(5) NOT NULL,
Price decimal(18,2) NOT NULL,
[Image] image NOT NULL,
Active bit NOT NULL Default('True')
Constraint PK_Item Primary Key (ID),
Constraint FK_Item_Brands Foreign Key (Brand) References Brands(ID),
Constraint FK_Item_Item_Category Foreign Key (Category) References Item_Category(ID),
Constraint FK_Item_Unit_Of_Measure Foreign Key (Unit_Of_Measure) References Unit_Of_Measure(ID)
);
go
Table insert is working fine. Before we go further I need to show the error that I am getting.
Msg 50000, Level 16, State 2, Procedure stpItem, Line 66
Operand type clash: image is incompatible with nvarchar
The above error occurs when I'm executing the command below and after that you would see the stored procedure
exec stpItem '','GG','2','2','2',123.12, null, 'true', 'false'
Stored procedure code:
Create Proc stpItem
#ID varchar(max),
#Name varchar(max),
#Brand varchar(max),
#Category varchar(max),
#UOM varchar(max),
#Price decimal,
#Image Image,
#Active bit,
#Update bit
As
Set Transaction Isolation Level Serializable
Begin Transaction
Begin Try
-- If it is an insertion
IF #Update = 'False'
Begin
Declare #Pre char(1),
#Len int,
#Next int,
#Start int,
#SetKey varchar(max);
Set #SetKey = '';
Select #Pre = Prefix, #Len = [Length], #Next = [Next] From Key_Generation Where Table_Name = 'Item';
Set #Start = 1;
Set #Len = #Len - 1;
While #Start < #Len
Begin
set #SetKey = #SetKey + '0'
set #Start = #Start + 1;
End
Exec('Declare #LID char(20); Set #LID = (select ''' + #Pre + ''' + right(''' + #SetKey + ''' + cast(' + #Next + ' as varchar(' + #Len + ')), ' + #Len + '));' +
'Insert into Item Values (#LID,''' + #Name + ''',''' + #Brand + ''',''' + #Category + ''',''' + #UOM + ''',' + #Price + ',' + #Image + ' ,' + #Active + ');' +
'Update Key_Generation Set [Next] = [Next] + 1 Where Table_Name = ''Item'';');
End
Else
Begin
Update Item
Set Name = #Name,
[Brand] = #Brand,
[Category] = #Category,
[Unit_Of_Measure] = #UOM,
Price = #Price,
[Image] = #Image,
Active = #Active
Where ID = #ID;
End
Commit Transaction;
End Try
Begin Catch
Rollback Transaction;
DECLARE #ErrorMessage NVARCHAR(4000);
DECLARE #ErrorSeverity INT;
DECLARE #ErrorState INT;
SELECT
#ErrorMessage = ERROR_MESSAGE(),
#ErrorSeverity = ERROR_SEVERITY(),
#ErrorState = ERROR_STATE();
-- Use RAISERROR inside the CATCH block to return error
-- information about the original error that caused
-- execution to jump to the CATCH block.
RAISERROR (#ErrorMessage, -- Message text.
#ErrorSeverity, -- Severity.
#ErrorState -- State.
);
End Catch
Could anyone tell me why I am getting this error, and how to fix this issue?

Answer 1

You are not casting non varchar variables to varchar here:
#Price + ',' + #Image + ' ,' + #Active + ');'
Try:
cast(#price as varchar(max)) + ',' + cast(#image as varchar(max)) + ...

Answer 2

cast(cast(#Image as binary) as nvarchar(max));
I used a nvarchar variable to convert it from outside then use it inside og execution command
Declare #txtImage nvarchar(max);
if #Image IS NULL
Begin Set #txtImage = 'NULL'; END
Else
Begin Set #txtImage = cast(cast(#Image as binary) as nvarchar(max)); END