SQL Select Statement Question.

I use an SQL Select statement to gather data from three tables and combine it into one for use as statements. The problem is people aren't doing their job properly and are creating invoices before the job has been moved into one of the tables in the statement. I am using an Inner Join but the problem is if the value is in one table and not in the other it skips the record. Accounts are complaining because invoices are in the accounts system but not showing up on the statement.

I need to have some sort of error or flag show up when a record meets the criteria but isn't found in both tables. What is the best way to go about this?

The code i am using is below. What am i doing wrong?  

	SELECT S_STRAN.ST_ACCOUNT, S_STRAN.ST_TRDATE, S_STRAN.ST_TRTYPE,;
		S_STRAN.ST_TRREF, INVOICE.MARKNUM1, S_AOIM01.M_REQNUM, S_STRAN.ST_FCVAL;
		FROM ;
		COMP_S!STRAN S_STRAN ;
		INNER JOIN  K:\NCOST\INVOICE.DBF ;
		INNER JOIN "K:\SSS\S-AOIM01.DBF" S_AOIM01 ;
		ON  INVOICE.MARKNUM1 = S_AOIM01.M_PONUM ;
		ON  S_STRAN.ST_TRREF = INVOICE.INV_NUM;
		WHERE  S_STRAN.ST_ACCOUNT = "ZUE002";
		AND S_STRAN.ST_TRDATE >= STARTDATE AND S_STRAN.ST_TRDATE <=ENDDATE;
		ORDER BY S_STRAN.ST_TRREF;
		INTO TABLE K:\TRANSDATA\EXCEL\STDATA\XYSTDATAT.DBF

Select allOpen in new window

Thanks