Cursor - Declare variable error

Question

Cursor - Declare variable error

mahmoodsaadi

SSC Journeyman

Points: 90
More actions
September 9, 2014 at 2:57 am

#311364

The below cursor is giving an error
DECLARE @Table_Name NVARCHAR(MAX) ,
@Field_Name NVARCHAR(MAX) ,
@Document_Type NVARCHAR(MAX)
DECLARE @SOPCursor AS CURSOR;
SET
@SOPCursor = CURSOR FOR
SELECT SOPTYPE, TABLE_NAME, Field_Name FROM dbo.SOP_Tables
OPEN @SOPCursor
FETCH NEXT FROM @SOPCursor INTO @Document_Type, @Table_Name, @Field_Name
WHILE @@FETCH_STATUS = 0
BEGIN
DELETE FROM @Table_Name
FETCH NEXT FROM @SOPCursor INTO @Document_Type, @Table_Name, @Field_Name
END
CLOSE @SOPCursor;
DEALLOCATE @SOPCursor;
It gives an error
Msg 1087, Level 16, State 1, Line 15
Must declare the table variable "@Table_Name".
The @Table_Name variable is declared,
If I replace the delete statement (DELETE FROM @Table_Name ) with (PRINT @table_name) it works and print the table names.
Why does the delete statement give an error ?
Best Regards,

Viewing 4 posts - 1 through 3 (of 3 total)

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ChrisM@Work SSC Guru Points: 186127 More actions · Answer 1

-- You can't specify a table name as a variable in a statement in TSQL. Your best bet is dynamic SQL: http://www.sommarskog.se/dynamic_sql.html

EXEC('DELETE FROM ' + @Table_Name)

-- or

DECLARE @sql NVARCHAR(MAX) = N'DELETE FROM ' + @Table_Name

EXEC sp_executesql @sql

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Sean Lange SSC Guru Points: 286590 More actions · Answer 2

And you sure don't need a cursor for this.

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Luis Cazares SSC Guru Points: 183706 More actions · Answer 3

I agree with Sean, but I feel that that's not everything that you do on your cursor.

To prevent problems if someone messed up with the data on your table, I would use QUOTENAME function to prevent SQL injection.

EXEC('DELETE FROM ' + QUOTENAME(@Table_Name))

Luis C.
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