Select from 3 tables

[chrisleon]

I am trying to select from 3 different tables, and retrieve a count.

I know that there is a record number in one of the three tables, but I cannot get it to return it to me. I tried 2 ways, neither worked.

What am I doing wrong?

select COUNT(*) as numtimes from dtsdata.iitmranktm,dtsdata.iitmrankop,dtsdata.iitmrankmg 
			  where dtsdata.iitmranktm.TMRECN = '$recnum'
			  or    dtsdata.iitmrankop.OPRECN = '$recnum'
			  or    dtsdata.iitmrankmg.MGRECN = '$recnum'

select COUNT(*) as numtimes from dtsdata.iitmranktm,dtsdata.iitmrankop,dtsdata.iitmrankmg 
			  where dtsdata.iitmranktm.TMRECN = '$recnum' and dtsdata.iitmrankop.OPRECN <> '$recnum' and dtsdata.iitmrankmg.MGRECN <> '$recnum'
			  or    dtsdata.iitmrankop.OPRECN = '$recnum' and dtsdata.iitmranktm.TMRECN <> '$recnum' and dtsdata.iitmrankmg.MGRECN <> '$recnum'
			  or    dtsdata.iitmrankmg.MGRECN = '$recnum' and dtsdata.iitmrankop.OPRECN <> '$recnum' and dtsdata.iitmranktm.TMRECN <> '$recnum'";

[Joseph07]

Is there any relationship between the 3 tables?

For example, is there any key in dtsdata.iitmranktm.TMRECN is the same as dtsdata.iitmrankop.OPRECN ?
Or I assume that in all 3 tables they have a same key which is $recnum?

[Piranha]

Exactly what count do you want to get?

The number of counts from table1 + the number of counts from table2 + the number of counts from table3?

Or any other kind of count, in that case describe what you want, with an example if possible.