On Tue, Sep 22, 2015 at 6:22 PM, Alex Magnum <magnum11...@gmail.com> wrote:
> Hi, > I am having a problem where I need to inject rows into a query result. > That is > > I have a list of add records, lets say car listings which I select from a > table. The order of the results are given either by the user or > default/initial. > > I now want to inject featured car adds after every 5th record. (coming > from the same table) > > Right now, I am doing this on the PHP just calling the query twice but I > am wondering if there is a way to only run one query. > I have no clue how you expect to "run one query" AND "so the original listing should not be affected". > The main problem is that > a) i am using paging so the original listing should not be affected > b) the injected records should not be in the results returned for the > current page. > I have no clue what these mean since if you don't intend to show them why retrieve the feature car ads (one d) in the first place? > > Any one having an idea how to solve that? > > Solving the ordering problem has a simplistic brute-force algorithm (you may need to fix off-by-one errors in the logic - but the idea holds) SELECT *, (((row_number-1) / 5) * 10) + ((row_number-1)) % 5) AS "rows_0_to_4_in_the_current_decade" UNION ALL SELECT *, ((row_number - 1) * 10) + (5) AS "row_5_in_the_current_decade" Now you have: [0-5] [10-15] [20-25], etc... as your "row index" where every "5" record is your injected row. Hopefully this helps - you have provided insufficient and/or contradictory information regarding your actual problem. David J.
