INSERT INTO @table, where @table is a variable

Question

I have run into a little bit of a problem: I want to create a procedure that inserts some rows in a table specified via parameter. So along the code I have reached this point:

CREATE PROCEDURE my_proc @tableName VARCHAR(30)
AS
    -- ...some code...
    INSERT INTO @tableName VALUES(...some values...)
    -- ...some code...
GO

This doesn't work so maybe I'm missing something.

PS: I'm working in Microsoft SQL Server Management Studio 2018

Answer 1

You can only use variables for constants in a query -- not for identifiers. So, you need to use dynamic SQL:

declare @sql nvarchar(max);

set @sql = 'insert into [tablename] values ( . . . )';

set @sql = replace(@sql, '[tablename]', quotename(tablename));

exec sp_executesql @sql;

Two points. First, if you are planning in on passing the table name using a multi-part identifier, then quotename() is not appropriate.

More importantly, passing table names around like this is almost never needed in a relational database. If you find the need to do this, you likely have a problem with your data model. I would guess that you have multiple tables with the same structure -- and these should be combined into a single table rather than multiple tables.

To handle quotes strings:

set @sql = 'insert into [tablename] values (''aaa'', ''bbb'', . . . )';

Those are repeated single quotes ( '' ), not double quotes ( " ).