Create a view with column num_rows - MySQL

Question

I need to create a view that has a column named row_num where it will be inserted the row number, just like an auto increment in a normal table.

Let's say I've this normal table:

| country | name | age | price |
--------------------------------
| US      | john | 22  | 20    |
| France  | Anne | 10  | 15    |
| Sweden  | Alex | 49  | 10    |

And so on...

The view I want to create is:

    | country | name | price | row_num |
    ------------------------------------
    | US      | john |  20   |    1    |
    | France  | Anne |  10   |    2    |
    | Sweden  | Alex |  5    |    3    |

And so on...

I can generate the row_num with a single select:

SELECT @i:=@i+1 AS row_num, testing.country, testing.name, testing.price
FROM testing testing,(SELECT @i:=0) derivedTable
order by name

But my problem is to combine the query above with the query creating the view. This is the combined query I'm trying:

CREATE OR REPLACE view vwx (country, name, price, num_row) AS SELECT mytable.country, mytable.name, mytable.price, @i:=@i+1 AS row_number
    FROM testing testing,(SELECT @i:=0) derivedTable
    order by name;

I get the following error: #1351 - View's SELECT contains a variable or parameter

I know I can't use a select inside a select with views but I don't see other way to do this view the way I want, but I'm sure there is a way to do this but I just don't know how. Probably with functions or procedures but I'm really new to them so I'm not comfortable with creating functions or procedures in mysql.

I hope I made myself clear otherwise I'm more than happy to explain myself in further detail.

Answer 1

Adding Row number to a query result - No View needed - One Query

SELECT country, name, price, @ID := @ID + 1 AS row_num
FROM testing,
     (SELECT @ID := 0) temp

Add the following to your MySQL connectionString: Allow User Variables=True;

Don't add "Cross Join" in your query to update your @ID variable.