In SQL, how can I convert a VARCHAR to a STRING?

Question

I am trying to do a BULK INSERT operation on SQL Server 2008 R2 using a parameter. However, I am having problems that the function expects a STRING where I'm passing it a VARCHAR. My SQL is below.

DECLARE @filepath VARCHAR(30)
DECLARE @current_symbol VARCHAR(30)

DECLARE symbol_cursor CURSOR FOR
SELECT symbol FROM stocks.dbo.description WHERE 1=1

OPEN symbol_cursor;

FETCH NEXT FROM symbol_cursor INTO @current_symbol

WHILE @current_symbol is not null
BEGIN
SET @filepath = 'C:\Users\stkerr\Desktop\stockPricing\' + @current_symbol + '.prices'
BULK
INSERT stocks.dbo.pricing
FROM @filepath
WITH
(
    FIRSTROW = 2,
    FIELDTERMINATOR=',',
    ROWTERMINATOR='\n',
    ORDER   ( [date], [open], high, low, [close],volume),
        ERRORFILE='C:\Users\stkerr\errors.txt'.
)

FETCH NEXT FROM symbol_cursor INTO @current_symbol
END 
GO

The problem is popping up when I'm executing the SET @filepath statement.

Any ideas?

Answer 1

In order to specify the file in a variable ( @filepath ) to BULK INSERT , you will need to construct dynamic TSQL and execute it.

eg

DECLARE @str_command nvarchar(150)
SET @str_command = 'BULK INSERT [Customer_Sample] FROM ''' + @SourceFilePath + 
                   ''' WITH (formatfile = ''' + @FormatFilePath + 
                   ''', firstrow =' + cast(@RowNumber as nvarchar) + ')'
EXEC SP_EXECUTESQL @str_command

Answer 2

there is no "string" type in sql. if you're having trouble with the set statement it's likely because you've given it a maximum length of 30 characters, and your text is longer than that.

if its the From @filepath thats giving you trouble, its because bulk insert won't take a variable in the from statement.

overall, i think your option is probably to execute the bulk insert via dynamic sql. build the statement up in a variable and then exec() it.

Answer 3

I agree with Mitch Wheat, Dynamic SQL is the way to go. You also have a couple of other things that need addressing I think. Your filepath needs to be enclosed in quotes, and I think there might be a stray dot after your error file name. Try something like;

DECLARE @filepath VARCHAR(30)
DECLARE @current_symbol VARCHAR(30)
DECLARE @sql VARCHAR(8000)

SET QUOTED_IDENTIFIER OFF

SET @current_symbol = (SELECT "tst") 

IF @current_symbol is not null
BEGIN
SET @filepath = "C:\Users\stkerr\Desktop\stockPricing\" + @current_symbol + ".prices"

SET @sql = "BULK INSERT stocks.dbo.pricing FROM '" + @filepath + "' WITH ( FIRSTROW = 2, FIELDTERMINATOR=',', ROWTERMINATOR='\n', ORDER   ( [date], [open], high, low, [close],volume), ERRORFILE='C:\Users\stkerr\Desktop\stockPricing\errors.txt') "
END 

PRINT @SQL -- Check out the result of this, and try and run it by itself.

EXEC (@SQL)

Good luck. Note my example doesn't work with dynamic SQL as Mitch suggested. Get it working first, then re-implement with Mitch's example.