Question

I have a number of rows from a database which I want to insert into another database. Since there’s quite a few rows I want to use the INSERT .. SELECT … construct in mysql. The statement I try to run is as follows:

set @rank := 1; set @currpoints := 0; set @currgroupcount := 0;    SELECT id, @rank := if( @currpoints = points, @rank , @rank + @currgroupcount )   AS rank,    @currgroupcount := if( @currpoints = points, @currgroupcount +1, 1 ) , @currpoints :=    points FROM characters ORDER BY points DESC , name LIMIT 0 , 30 

The problem is that I can’t insert the selected rows into the database when the result has more than two columns. Is there any way I can do these needed increments without returning the expressions as columns? If it isn’t possible do you know what i can do as an alternative and still be able to get the performance gain that lies in using the INSERT .. SELECT … construct?

Answer 1

INSERT INTO new_characters (id, name) SELECT id, name FROM (   SELECT id,   @rank := if( @currpoints = points, @rank , @rank + @currgroupcount ) AS rank,    @currgroupcount := if( @currpoints = points, @currgroupcount +1, 1 ),   @currpoints := points   FROM characters   ORDER BY points DESC , name   LIMIT 0 , 30 ) m