conditional IF

Hello. I have a query whice look like this:
select a,b,c,d from table1;
Now - when pressing a cell in the first column we are jumping to another report with the value as parameter (called- p_param);.

In the other report the query is:
select * from table1 where a=::p_param.

What I want to do is taht in the first report I'll will check if thesecond query return any result and if so to leave it as a link. If thesecond query does't return any result (zero rows) to remove the link sothe user won't go to an empty report.

So first i need to know how to check in the first report what will be the result of the second query.

Can u help me?

Thanks in advance,
Roy.

Thank. My message already been replayed,

I just changed my query.

thanks :)